Billed after cancelation

In February 2025,I spoke to Telkom and requested to cancel my service earlier as I had been retrenched and will no longer afford payments and they gave me a cancelation fee that i paid the following day to get services canceled,then end of the same month they billed my account and i thought it maybe the last one and those were admin fees,now end of March 2025 I get billed again and I send the cancelation consultant an email to find out why and no response from her then I sent an email to the customer service,instead i get an sms that I must pay for my services of which i canceled and paid for and one is taking any accountability and this will impact my credit record negatively