Disgusting service

I am having a tough time with Vodacom, I have a wifi contract with them,they usually debit my account on fhe 1st of every month.in August my salary delayed and the debit order did not go through so I paid double the following month including the penalty fee. This month again my payment delayed when Vodacom tried ro debit there were no funds in my account my bank account was then on a minus the amount that Vodacom was supposed to debit, a few days later I got paid and the minus amount was cleared on my account. Now yesterday I got an email from Vodacom that my account is in arrears I must pay double of my installment including the penalty fee,I called un this morning and spoke to precious I explained to her what has transpired, she kept saying I still owe double payment, I don't understand that because when I got paid it was cleared on my account. She then escalated my complaint and said her manager will call me back in an hour that was un the morning till now I am still waiting for the call. I have received a statement dated October 2023 on that statement is showed I owe R320 but they now saying I must pay double the amount

Another issue when I got this contract I was quoted R299 and sent the quote I still have it to my surprise they always debit R320 I have logged a complaint before and was told it would be sorted out and nothing was done. Their service is terrible