useless employees

I received smses from them a while back and after i paid my account to van rensburg pathology in June last year they still carrying on to harass me with smses. After speaking to paulnita she said that i must send my proof of payment to them and will sort it out this was supposed to be sorted out. Ob the 3rd of feb i yet again received an sms from them and i told them if they not willing to do there job i will do it for them i phoned van rensburg pathology and spoke to them and the sorted it out in 10 min that it was paid. Guess what i received an sms today again and i phoned them but all of a sudden everybody is busy in the office Even the boss cant even take a call of there useless employees. Paulnita sent me an email that was dated from the 3rd of feb and stated see still no payment received so that means they are not doing there job .they like to harass people.