LML flash gone wrong

Situation- Recently purchased a 2012 Sierra 3500 Denali. Truck was tuned with a PPEI autocal. The previous owner had swapped in 4.56 gears about 50k miles ago. This set off the ABS light and warning for obvious reasons. Previous owner didnt care about the light and drove it this way for 50k miles. I wanted to correct this issue. I had the "tuner" at the shop where I work use HP Tuners to try and change the gearing in the pcm. That failed and now the truck will not start or communicate with the autocal. Gives a U0100 no comm. code.
Can the pcm be recovered with a proper flash? Is there anyone out there who can do this? Should I buy a used/Ebay pcm and start over? Then I will.need a new VIN licence for the autocal. Truck is already deleted so no.one seems.to want to help me. Even with just a stock file to start with. Maybe I'm just not looking in the right places? Any guidance would be appreciated

You have purchased the hand held tuner of a particular tuning company that happens to use EFILive's hardware to deliver their product. AutoCal is linked to that tuner's FlashScan as the exclusive provider of tune files. The EFILive product is simply the tuning software and hardware - it is not a tune. Together the software and hardware give users the tools to write tunes. EFILive does not provide tune files, tuning advice or tuning support, but we do provide software support and hardware support for the EFILive product.

AutoCal is linked to your Tuner's FlashScan; this means:
1. Tune files from anyone else will not function on your AutoCal. Each tune file needs to be signed by the Tuner's FlashScan, so any recovery file needs to come from your tuner.
2. Your tuner controls the license slots that are available for your use. You may check the license slot availability by following the instructions available here https://service.efilive.com/kb/artic...and-auth-codes.
If you have no available slots, your tuner must first increase your slot count.
3. If you have an available slot you may purchase a VIN License, however the ability to license a new ECM (even a replacement ECM) is dependent on the tune file security the tuner applied. (Specifically, if they used controller serial number as tune file security your new ECM will not have permission to flash)

In all scenarios you are best to discuss the capability of your AutoCal with your Tuner given the configuration of the device is dependent on how the tuner manages their business.

Cheers
Cindy