I paid an account fully and I was told to wait 24-48 hours and even the amount I was paying got some...

I paid an account fully and I was told to wait 24-48 hours and even the amount I was paying got some interest even after I did a settlement which we didn't agreed on , now I'm waiting to my clearance letter to cancel the contract but I'm always told to wait and it been 7 days since I paid up the account