Bad Customer service practice

Paid my monthly instalment in April to account number given by their call center consultant. Till today no update on my account of whatever I paid using their bank account provided to me. I sent few emails to their customer service team, and every time I get response " Please provide your Address, contact etc. for us to assist. Done that so many times. Now they need me to pay say I owe them, what I have already paid. Where did my money go? Since you guys are the one provided banking details to me?