Chillafish Bikes no addressing customer complaints

I bought my son a Chillafish balance bike in Dec 2020, just to notice that you can't adjust the seat post as the ***** stripped. So I called them to ask if they can either repair or replace the bike (2 months old). They confirmed they will replace the bike for me. A week after my conversation with them, I phoned to ask for an update as to when the bike will be sent, tracking details etc. It is now 3 weeks later I can't get hold of them via the phone (it just rings) and they are not replying to any emails. I have no other avenue to get into contact with the company and would really just want to get a bike that works for my son or my money back.