I was charged twice when changing the plan
I switched to 65 plan and found out it doesn't support hotspot, so then I switched back to 45 plan. At that time I had already paid 65 to att. After switching to 45 plan, att told me my plan did not renew on schedule and asked to pay to start my service. After I paid for 45 plan, I saw 0 balance on my account. So how can I get my refund?