Charged Failed debit fee for paying EFT before dbit order date

I have a debit order for the 25 th of every month with Cell C for the amount of R 249.00 . However in the month of May 2019 i paid R250.00 on the 24 th of May 2019. Their statement to me shows payment received on the 24th of May. Cell C charges me with a R70. 00 failed debit fee. They will not reverse this as i should paid 10 days before. You get charged for even paying early yet there is still 6 days left in a month. This is really poor service from Cell C.