Very unhappy customer

I ordered 2 fitness bracelets for my kids for Christmas on the 2 November, I waited just over a month for my order.. then I decided to make sure everything was working properly before I had disappointed kids on Christmas day... and after being a bit skeptical about buying from this company my gut feeling was right.. one bracelet is not working, so I emailed them, no response... I eventually found out that you can send them a message via messenger.. sent a few messages then finally got a response... I told them that one of the bracelets are not working and then was told I must do this and that and after explaining that I have got one to work means I obviously know what I'm doing then was told that if I send it back I would have to pay courier fees if the item is to be found working properly... I told them to collect the item, and someone was supposed to contact me regarding a pick up date, nothing has happened yet... this was on the 8th December.. I have since been blocked on messenger and I can no longer get send messages... I explained this was for my kids for Christmas, and now I must decide who gets something and who doesn't... This company needs to be investigated!!! They are clearly dishonest people.... absolutely disgusting!!!