The worst store ever! Came there on first day of ...

The worst store ever! Came there on first day of their opening , bought a chair. Unfortunately it didn t fit our space. When returning they charged me one more time, my mistake that I didn t check it right away. Came to the store the next day to and they refused to give my money back!!! Saying that that only can give me a store credit.
I totally understand that they just opened and there there maybe some mistakes ,but you have to be responsible for those mistakes.