Cancellation

Sold my car almost 4months ago, logged a query for cancellation twice and tried cancelling via the WhatsApp; for Netstar to only call 3months later following up on payments, yet I have notified via the platforms recommended to me. Spoke with a lady who said she was going to call me back and NEVER DID. Spoke with another lady who said was going to leave a note under my profile, still I am getting the same calls with no resolution. Emailed on Monday, till today, no one has responded yet on my other car which I now want to cancel due to this bad experience, someone has been responding real quick, meaning the other email is just being ignored. After close to 6years with Netstar (since November 2019), i feel it's not fair.