Loan agreement!!!!!

So i have a loan with Capitec Bank , we signed contract for Debit Order on the 25th. The last few month the debit order goes of as they like, okey so it did not bother me as my company did change payment dates and i get payed earlier, and as soon as my money is in account the debit order goes of... today they send me a sms and told me am in arrears as i did not pay my loan this month. I called them and told them i havend even got payed and that the contract stated 25th of every month and they told me its not true Iam sitting with the contract infront of me. They are breaking contract and puting my name as a bad payer!!!! Poor! Poor! Worst!!!!