what to do when a business owes you money on a refunded purchase but you never recieve compensation

i have been in a battle with midea american corp since june about a portable air conditioner i purchased at a walmart in store. i lost the reciept so i contacted midea for the refund instead of going through walmart because you need a reciept to refund items. they have a 30 day policy for returning electronics as well so they can no longer assist with the matter, i just spoke to refund department at walmart today and they told me to go through the BBB or a lawyer. i have waited months for  a refund check only to be told it was lost because they didnt have my address correct in their system. I have spoke to a woman claiming to be head of cutomer service department and was told i would recieve an update with in 1-10 days this was at the beginning of august. i called back after 9 days of waiting just to be told that theyre still waiting on the refund department to update them and they have been waiting for an update after putting an extension on it back in july after mailing it to the wrong address. i am told i can not speak directly to the refund departement. i did use foul language due to me being frustrated which lead a different supervisor hanging the phone up and blocking my number. all i want is my $320.60 check. my house just flooded and this money could really help us right now.