Disgusting service

I bought a Christmas tree which was delivered on the 15th December with legs missing. Did a return request same day and booked collection for the next day which never happened. Had to harass them again with calls as their website wouldn’t update ever since I requested the collection. They collected on the 21st and received their item on the 22nd and I’ve been chasing them for my refund ever since. Call after call everyday and nothing is being done about this. I want my money back and I will not stop till I get my money back