Poor service 3 weeks

Two cellphones *** & *** teceived a statement showing a credit of 3351.60 after account *** was settled we requestef to settle tje second cell no quote received 1286.82 the settlement qoute showed a credit balance if 1094.66 after the settlement was done. Meaning they had to pay the difference over to us. After several calls and task logged with autopage no joy. I wouls please like help resolving this as simple marhs 3351.60 minus the settlement just over 2000 tells me they need to pay the eifferenxe over. Please contact my son Steven as he paid the account.