complaint

i bought three pieces luggage set last year November,they delivered and i found that one is damaged . I requested return they collected the one that is damaged and after they sent am email that i must return all of them.i came back from home this january then asked them to collect then they collected and i have proof of everything,i also sent them prove.Till today they never resolve my issue i ask refund they don't want to refund me ,i need help with that