Bad service telkom

Terrible I have a phone contract with Telkom on the 25 they debit my account however on the 25 December it rejected I then went and made a manual payment on the 27th of December 2019 as on the statement it said it’s due 31 December 2019 I paid it manually at pick n pay and this month they send me a statement saying I owe them R601.00 when I ask how ?they tell me because it rejected I said it rejected but I made a manual payment before 31st as per the statement telkom is ripping people off yet they can’t even explain this I made a payment so I don’t owe them now all of a sudden from R399.00 I now owe R601.00 what’s worse they have listed me I tried going to one of the financial institutions they couldn’t approve me as they said I owe telkom when I called the consultant couldn’t told me stories I don’t understand how can paying two days late get you listed without even them sending you any communication I can’t wait to finish paying this account n leave telkom and their terrible services will never recommend it to anyone.