Voadcom "red hot deal" stay away

I currently have a contract with vodacom, whereby i receive 120mins a month and if any further airtime is required i top up. For the last 3 months my bill is very high. As it is a lock contract i don't expect surprises at the end of the month. I tried numerous times to contact them via email and calling and had no success. This morning i finally got a hold of them and was told i dial *135 and selected a red hot deal , not even sure what that is.Now my bill from R140 per month is almost R2000. On my defence all i tried going was convert the airtime supp**** to data and they say i selected monthly instead of 30days. I converted the airtime , because every month the airtime disappears even if not in use. They are not willing to cancel what happened maybe by error and i will continue being billed as the account is in arrears of R4000 in 2 months. I don.t have money like that to pay back due to covid and work situation. According to them, this normally R140 account will continue to be charged R2000 every month now until i pay the R4000 owing. I have had contracts with cell C and have never had issues like this. Why put options on prepaid like this , if people wanted data or airtime then they will purchase it the normal way. This is just a way to **** someone. I regret ever taking a contract with vodacom and will not be liable for something that was done in error and they not willing to help.