Nobody return your call

I made an arrangement with VVM to pay an arrears account for a 3rd part for Telkom. I told them that I will pay on the 20th, which I did, yet they keep on phoning me and telling me it has not paid. I contacted Telkom and they confirmed that the R400 has been received. I tried calling VVM, nobody answers the switchboard or it only goes dead, I eventually got hold of the operator, she then said she will get somebody to phone me, nobody does, I tried to register on their website, they don't send you the return email to activate your username. I am at my wits' end with these people. I want to confirm the future payment arrangements, but cannot get hold of them, SO I MAKE IT HERE THAT FROM JANUARY 2016 IT WILL BE ON THE 25TH (TWENTY- FIFTH) OF EVERY MONTH FOR THE TELKOM ACCOUNT. I REPEAT : 25TH (TWENTY-FIFTH0 OF EVERY MONTH FOR THE TELKOM ACCOUNT