Frustrated

I missed a payment on the 25th of December and part paid on the 4th of January with R312 then I paid on the balqnce on the 24th January plus the subscription amount which totalled to 938 but for some reason my service was cut because I am told that I owe R625 for December. I have been calling since yesterday as my service have been suspended and the only answer they give me is that the matter has been sent to collections department and they will call me back but I have not been assisted since.