evolution world wide limited freebirdstablets deals on 10" pc tablets shanghi China

I bought a 10" pc tablet from evolution word wide also called freebirdstablets in thier email to me. it worked fine for a short time and i sent it back to them.  after a few weeks and nothing from them , istarted to inquire about a refund or they could send a replacement . they said they were sending me a replacement and it would take ,i think somewhere around three weeks for me to get it.   well it has been much longer than that and last several times i tried to contact them about it , was unable to contact them trough tier email. which is all i have to look for them. so they owe me a replacement or refund. i don't know how to get them to do that. can't contact them.  please if there is any thing you can do to help me in this matter, please any help will be apprciated.  thamk yo much