Residence Card has not been received after 18 months yet!

Hello,
this is my story basically.I came to the UK on EEA family permit in 2012. I then have applied for a residence card which has been refused with the right to appeal. and so I did.
Three months ago, I have appealed against the refusal and the tribunal judge has withdrawn the decision by the Home Office and demanded that I should be issued with the residence card immediately.
It has been three months now and without anything from the Home Office. my solicitor has contacted them several times, but without any response from them.
I cannot prove to my employers that I am entitled to work here in the UK. The reason I am posting this now is, I have recently received an offer letter for a job, but I cannot prove my right to work here to the potential employer. Although, I have showed them my NI letter, UTR, a letter from the solicitor as well as the headed letters sent from the solicitor to the Home Office, they want a letter from the UK Border Agency(who are not responding) which makes it an almost impossible mission.
I have also contacted my MP, and was told to wait for them to contact me.
Could you please advise me on what other alternatives I might have to prove my eligibility to work here in the UK? should I send the team dealing with my case a letter to explain my circumstances?

Thank you for your help in advance x

What was the resolution?