If you are absolutely sure you haven't used it in anyway pertaining to a ban, it's likely your account was breached sometime in the past and used for spam/malicious purposes, resulting in a ban while you were away and unaware.
Likely you were either phished for those account details or your password/username was a re-use from a breach of another place where you used the same user/pass combo.
Check https://haveibeenpwned.com/ on your email to see if you come up in any breaches.
Telegram is not private. The information security community recommends switching to Signal to avoid the next privacy scandal where once the server is hacked, private messages leak from the server.
Unlike Telegram that only protects one-on-one messages from mobile client to another, Signal also protects messages from desktop clients, as well as group messages.
It's free, open source, and does not collect your private data. Telegram is a product by Pavel Durov, the Mark Zuckerberg of Russia.
Get privacy hider
You can select apps to install and hide here (Kik) and you can change it to look like a calculator and have a pin to unlock