Discovery Cash Back failure

Discovery called me to say I had a lot of money due to be paid to me from Healthy Eating Cash Back as my bank account details on the system were old so payments had not been made. I updated the bank details as requested and was promised the money would be paid. Weeks have gone by, I have logged numerous calls and been promised payment multiple times but have still not been paid. I have been counting on getting the funds am an now frustrated and disappointed.