Telkom ****** us R350 please help

My wife was paying telkom Sim contract and then defaulted for some time, then she made an arrangement and payed all the money she was owing. Then she called to find out if she didn't owe anything. They told her she was clear not owing them, in fact they said she paid more they were owing her 350 that she must claim. They gave her a number to call, she called that number and they said we see that we owe you give us your account. The money did not come through even today. When she calls today the guy says maybe she owes a landlines, we don't own any landlines at my house. Then they said the money was taken by interests that we don't know, please help