Amazon - Money not refunded and the company have blocked my account from ordering COD

I ordered two pieces bath and storage self from Amazon’s on ** January **** . I returned the product because one of the suction was not working ,they took the product but I did not get the refund . I called their customer service ,they assured that the refund will be made soon , I waited for almost a month, then I called back ,they again assured that they will look into the matter , but that did not happen for another one month, then I tried to call back again , its not responding , more over they have even blocked my account from ordering COD. I cant even check on the thing I save in my cart . Every time I go to my cart it went back to the home screen . I’m not bothered about the money but why do they have to block my account. I’m the one who’s feeling guilty here...