Trouble with product

I bought a Macbook Pro (Retina 15") from Best Buy at the end of February 2016 and Best Buy installed Webroot SecureAnywhere.  I am using  El Capitan 10.11.6. and the Safari browser.  I set Webroot up with the secure pw feature.  
 
Sometime in April, I began to have a keyboard issue when filling in forms downloaded from the Internet  --  though I typed at normal speed, the letters appeared with about a 2 second gap between each one of them.  Working with Apple Care, all we could do to resolve the problem was turn Webroot off.
 
Weeks later, suddenly Webroot, Firefox, the Office for Mac applications and iTunes vanished from the computer when I was llying in bed one evening reading the news at google.com/news, my default web page.  All that I saw was the icons in my Dock with "questionmarks" in them.
 
After extensive work with Apple to try to resolve issues, including multiple reinstallations of the OS, Apple gave up and replaced the computer.  I might add that no fight on my part was required to have it do that  --  the Albuequerque Apple Store rep came out (nearest store, as I live in Santa Fe), told the young man signing me in to not do so, said he'd reviewed the case notes and then said "here's his new computer."
 
Apple's engineering group claimed it was impossible for portions of OS to be deleted, but concurred that that HAD happened, downloaded reams of data from the computer, and, to this date, hasn't gotten back to me with an explanation.
 
Yesterday I did a Webroot Security Report ("all clear"), ran the system optimizer and analyzer, and changed the time of day that my scan occurs.  I then sought to open Webroot to see what other utilities were available, only to find that the icon was no longer at the top of my screen and the following applications were gone:
 
Webroot
iTunes
iBooks
The Office for Mac ones
Firefox
HP printer software
 
I then had a 2+ hour online Geek Squad tech support session that included an attempt to reinstall Webroot.  The download would not be accepted for transfer to the applications folder and could not be removed by the tech support person despite many different kinds of attempts to get rid of it.  It was a file only 6KB in size!
 
The tech support person concluded the Webroot directory was corrupt and suggested I go to my local Best Buy and make an appointment to resolve the issue, as Best Buy had tools that could do it booting outside of OS.  However, the store wanted me to leave the computer for up to 5 days, which is a "dog that won't hunt" for me because I am an attorney and use the machine constantly every day w/o a backup machine.  So I talked with the Apple Genius Desk in Albuquerque (I live in Santa Fe, and that's the nearest Apple Store), who said I could make an appointment, but ought to check with Webroot Support first.  I had a call with them this morning, and after about 30 minutes they successfully removed the corrupted file.
 
I recovered iTunes from an update at the App Store, reinstalled the Office for Mac applications from the Microsoft site and the other applications except iBooks online.  Since I never use it, I'll simply wait until Apple does an update and restore it then.
 
After my tech support with Webroot, I got a follow up email saying in pertinent part the following:
 
"Just please be very careful with the system optimizer, only use the default settings on that. Also, please avoid or be EXTREMELY careful using the "Delete Files Securely" button under system optimizer tab in utilities. If you used the "Delete Files Securely" button for system optimizer, that could have been the cause of the issue you experienced where your important apps were erased."
 
To the best of my recollection, I used the default settings with optimizer and did not use "Delete Files Securely".  in any event, I find the final sentence amazing  --  Webroot appears to KNOW that if you elect to "Delete Files Securely" with the optimizer, which is only supposed to remove unnecessary files, IT MAY ERASE APPLICATIONS, INCLUDING PORTIONS OF OS, WHICH APPLE TELLS ME IS NOT POSSIBLE BUT AGAIN AGREES HAPPENED!
 
I am not a technical person at all.  But I am a practical person, and I think that if Webroot knows that use of "Delete Files Securely" with the optimizer may result in unintended and unwarranted erasure of applications, it ought to resolve that issue or HEAVILY PUBLICIZE IT.  After all, it is in the security business!
 
Throughout this recent episode, I've also had extensive conversations with a senior Apple Care advisor.  She has been in that role for 7 years and had never before encountered a situation where a portion of OS vanished.  She has obtained the case notes from the prior time this happened on the original machine and again is raising the issue with Apple engineering.
 
In any event, I am curious if anyone in the Community has encountered similar problems or has any comments or suggestions.  For the moment, I am not reinstalling Webroot because if problems reemerge, "shame on me!"  For me as an attorney, time is money  --  time = my inventory  --  and with the time I've wasted because of all of this over that past several months, I could have purchased 10 Macbook Pros and taken a vacation or two.
 
Thanks for any input.
 
TomC