Changed Land Line issues

Hi guys long story short I signed up to a new land line contract as a company approached me and said they could buy me out of my current deal with BT, and that the whole process would be seamless.

2 months on I have jumped through hoops such as signing extra forms and paying invoices. and still not been bought out of this contract which I still owe BT nearly £400.

The new company said they would pay it to me now apparently and it's my job to pay off BT (not as seamless as first explained) I have proof of them promising me this money over email.
So I'm asking has anyone had anything like this happen to them? Did they finally get the money? And what are my next steps legally to get this money off them?

I have already submitted a formal complaint.

The communication ombudsman can't help, and neither can ofcom because they are a broker.
Thanks in advance!