JET / RCS REFUND

I have sent a Refund request on the 7th of April (ACC NUMBER ***) I have sent all the required docs and they keep on asking me for proof of overpayment yet I explained the payment came from my company and therefore I cannot sent proof to them. Its been more than a week waiting for my refund and they are not communicating with me. My account was closed in 2019 and they are telling me about a monthly service fee that is applicable, I don't understand why am I getting charged to get my money back. How long does it take to process a refund , they also take 48 hours to respond to emails. mY NUMBER IS ***