Should I be worried about my old classmates using my phone number for Telegram?

Yeah, it's definitely a bit concerning! If they're using your number for Telegram, it raises some red flags. Why would they do that unless they have something to hide? Luckily, they can’t really hack your accounts just with your phone number alone—still, it's wise to stay alert.

You have control over your phone number, so you can check what they might have done. If you’re really worried, it’s a good idea to lock your SIM and even consider getting a new number. Better safe than sorry!

Just remember, while your number alone doesn’t give them access to your accounts, it’s good to be cautious. Maybe take some time to change your passwords and enable two-factor authentication just in case!