Debt collection after settling account???

I settled an account on November 2023, since then I have been called by a company called VVM, which I have been paying due to no official email or assistance from Telkom, but now they want to double the repayment amount, which is ludicrous since my account was paid in full December 2023, please advise how VVM has received my information and keep saying I owe R1823 on a Telkom Internet account that no longer reflects on my customer dashboard