Hey there Z4RO, welcome to the forums. Sorry to hear you got disconnected, causing an MMR loss and a ban. That certainly sounds very frustrating.
I've mentioned in Keenact already, and just to reiterate, we've had no reports of issues with our servers over the past few days. As such, I'd recommend making sure to check out
connectivity guide, and make sure to follow all of its steps (but especially resetting your network hardware, going wired if you can, and contacting your ISP to request their help in setting up your router correctly).
If you find you continue to have connection issues, let me know, as I'll have further troubleshooting steps you can try.