Help unable to change name servers

[John Jacks]

Hi ,
I have registered my domain called musiccornerltd.com through a company called Fasthost.com .This company is not responding ( infact they look like gone bust )  to my request of changing name servers so that it points to my web server in UK. The company which is actual registrar for the domain namecheap.com are not helping because they are saying they have no contract with me .Please can anyone advise what course of action should I take .
Thanks
John