Temu Denied My Refund - Customer Service Gave Me No Clear Answer

Getting a refund from Temu is a complete regret. They keep sending the same message over and over, claiming it’s proof that they’ve issued the refund. However, when I called the bank, they said, "If a refund had been processed, it would have appeared in our system the same day." I even checked multiple times to be sure, but there was no trace of the transaction. They also told me to "contact the institution where you made the purchase," but reaching Temu is impossible! Their customer service is either unresponsive or gives vague answers that lead nowhere. Now, I don’t even know who to complain to.