Poor Quality Prawns

Purchase cleaned and deveined 400g prawns from Checkers Emmarentia. I cooked the prawns and found them very rubbery. Totally disappointed with the quality of prawns. The prawns looked really appetising in the packet but when cooked were so rubbery it was worse in texture than overcooked calamari. I lodged complaint with them and they didn't even have decency to respond so much for their Customer Care and respect for their customers down the line. Checkers though did.

BTW, The prawns were definitely not Overcooked.