I have tried moving to EE from Bt in a EE shop but am unable as they claim there is an alarm or monitor connected.
I haven't got either, tried phoning customer service, I was cut off after waiting for ages. Will try SKY to see if I can move to them easier.
Try phoning retentions and they should be able to help you move to EE 0800 7831401
When you were told there is a problem with line did they say it was a 'bridge tap'?