Double debited and not refunding till today

I was not assisted by rain agents and keep on hanging off while I'm on the phone, I have 5 different references but not getting any help. My problem was they did double debit my account for the first month I was with them and I called them 5 times and they did check and promise to fix and say escalated and the supervisor will call and fix the problem. Even today no one has assisted and my phone are being hanged off please assist. I have a contract of a 499 unlimited data my first month was last month but they debited 899. My number is *** as my customer number