Creaking bed /shoddy workmanship by Sealy and Matress King

Purchased a bed from Matress King about 4 months ago to date they have had to replace it because of shoddy workmanship I'm now sitting with the second bed giving me the same problem creaking I'm struggling to get them to refund me they keep referring me to Sealy and Sealy does the same refers me back to Matress King. The salesman his name is Zain called me the other day and says they can upgrade the bed but I need to pay the difference and all I want is my money back and they can have there creaking bed.