Blocked Account

Payments were made in December and POP was sent through. Despite that I still got bombarded with sms'es stating I owed money. Since December the POP's were sent through 6 times and yet they still state that they "didn't" receive it. I have called them 12 times since 22 January, but my lines were cut 30 January. They still refuse to unblock it even though they have confirmed,on more than 1 occasion, that they can see the monies have been received. They keep promissing that they will contact me within 24 hours and guess what...I'm still waiting!

What more can I do? I guess the next step will have to be taking legal action.