Refund from iua insurance kept at westbank account and they are responding to emails sent service @westbank.co.za

I bought gwm steed 5 bakkie at burch more Sandton auction that was Nov 2019. I took mechanical warranty with bidvest or burch more which was including in car finance with westbank. The car had a hard starting I reported to westbank whom they referred me to iua .they kept me running around from January 2020 to may then I decided to cancel contract with them. They refunded the to my westbank account but now at westbank they needed proof of payment of which I 've send several emails with proof of payment from iua they said is going to be paid within 48 hours and it has been 3 weeks no response. If I call them they keep transferring me until the phone rings unanswered . I m stuck with non running and is finance by the same bank which is refusing to pay refund that was paid to them in order to fix the car .I even think of making stop payment so that I can get clarity ?