Alpha Telecom

I would like to just say that I have had my account with Alpha Telecom since 1996 and have always managed to have a reletively healthy relationship with this company, until a couple of years ago, when the service was deteriorating chronically. This is also a company who would phone me up on a weekly basis to try and encourage me to buy more credit - even though I always had £100 or more in the account! They would not take no for an answer and now the company has gone bust - with £150.00 of mine - still in their filthy little hands! I was reassured that I would have this money back into my account within a 2 week period (even though I told them that I wanted it done immediately!) Before I decided to "close my account" it had not been working properly for weeks and weeks without access. I only managed to speak to someone, but posing as a "new customer". Now, unfortunately, not even that is useful, as none of their numbers are working.
If there is anyone who knows how I can take the legal route of getting this money back, I would be eternally gratefull.
Kind regards,
Natalie Callaghan