How do I request refund from Apple for an unfulfilled service purchased on Telegram?

If it is not eligible for a refund I am afraid that you cannot apply for a refund

Take it up with Telegram if you were scammed on their service. You will not get a refund for your purchased stars, since you successfully received them. Apple is not responsible for what you use them for on Telegram. That is like buying an Amazon Gift Card through Apple and thinking Apple is responsible for what you purchased with the Gift Card.

AlfredGaz1 wrote:

Well i refunded once this way so it should have worked.

Nope. At times, Apple may provide a compassionate refund, but it should never be expected. You are actually less likely to receive any further refund after you have already been given a compassionate refund. Have you contacted Telegram for why they are allowing this type of fraudulent activity on their service?