After paying my loan online, I was still in arrears and I was debited from my account so I've paid for one loan twice in one day

After paying my loan online, I was still in arrears and I was debited from my account so I've paid for one loan twice in one day. I cannot get ahold of anyone in a call centre and no one is assisting. This is absolutely atrocious and I would not recommend anyone do business with them.