*****ed my signature for a high package I didn't ask for

I signed up with vodacom for fibre. The application was done via whatsapp by JP (***). He sent me a list of packages they have. I told him I wanted the R 449.00 package. He did the app it was successful and they installed my fibre, the end of June i=I received my invoice for R 599.00. I called JP he told me I must call customer service they will help me. Called them they told me there is not R 449 package available and that the contract I signed has my signature on it with the option of the R 599 package. I told that that cant be as I did not fill out any paper work and even so I told the sales person I wanted the R 449 deal. She told me she cant help me and can send me a copy of the contract. Upon receipt of the contract the contract low and behold the R 599 deal was ticked with a signature on the application that was not mine. I called back and told the lady I never saw this form before, I never filled it out and that is definitely not my signature on the form. She told me she cant help me she can only cancel the fibre but I will still be liable for the bill. which I don't mind paying but the only the price I signed up for. Anyways they took the money (R 599 plus the pro rata of R 599)as its a debit order. The call centre lady told me I need to contact the sales person and he needs to fix the problem. I called JP he remembered me and he told me he knows I took the R 449 package and that he will send me the contract with the R 449 on it. I sent him my email address and he said he would sent the copy through. Its been now 5 days later, still no copy of my contract and he is not answering my calls. I called him 7 times this morning and he is not answering, he is not reading my whatsapp messages either. So be careful. these people are ********** and they con artist. I am taking the matter further as I still have the whatsapp application I did with the salesman.