Debit dates

The call centre of absa will contact me on ********** 021, and ask to change my debit order from the 25th to the 24th now this is quite irritating and i have told them multiple times that there is nothing wrong with the time the account gets debited and yet they keep on phoning in this regard, so this bank clearly enjoy to try to change things and not forgetting that a contract has been signed on a specific agreement, thus if you want to change the date then lets re-assess the account and change the interest and change the contract in total, so kindly ensure that the date stays the same and also ensure that these calls to change contract paticulars stop.. as i have asked the call agent last time to leave as is and document as that as well that further calls will not be entertained pertaining to this