Refusal to help me with an expired card, polo prefers to just ***** my money

I was very disappointed when I walked into a polo store and asked for assistance with a gift card in my possession, the only response I received was ' its expired and your money is gone'. we have been supporting this brand for over 10 years, and have spent 1000s on it. I had explained to the assistant that we had moved houses and this was lost in the move, that we recently found, surely there is a way to help us sort it out, and the answer again, your money is lost. I may have lost a few 100s, but you will lose more without my support, but i guess me business is not valuable to you.