Let me fix that real quick:
NEVER reply to PMs from anyone ON Telegram who is not in your contact

Telegram is a place that I bet that most scams thrive than in other social media platform basically because of the way it is created and some random person can find your contact and send a pm to you. However, I think that this can be fixed in the settings area.

Even when it is fixed, the rule of thumb is in the first sentence.