Yes, error messages like "Please prohibit the use of third-party plug-ins or applications." is related to using BlueStacks and it will result a account ban for players on PC.

Gameloop

Your only option to play COD: Mobile on PC is to use Gameloop [https://www.gameloop.com/], because it's the official emulator for the game.

Unbanned Request for BlueStacks

It's not possible to request a unban for getting banned for using BS. This type of bans are permanent.