wanting to take their money early

Its the 2nd month now that Capitec wants to take the money for their loan much earlier than what we agreed upon. They tried to take the money today and then sent an sms saying I must deposit the money into my account today so they can take their loan repayment for April. My calender says the 30th of April is end of month when I get my salary.. not the 24th of April. I'm extremely unhappy with this. And its the 2nd month now having problems with this bank.