I need help on resetting my phone number on my account

I've emailed, emailed customer service, no one won't get back with me, it still has my old number on here because I want to redeem for my gift cards, they can't cause they still got my old number on here. I don't have my old number, no more, I got a lot of coins, I don't want to get rid of them, can someone get back with me as soon as possible, I appreciate it thank you