Oh dear it sounds like installs have got it wrong
The best thing to do is to lodge a complaint with C/S .Also use the resonce tek service on the ntlworld home page its under tell us what you thinkAlso the person whos no.you have should call in and say his no. is off and if you ring faults and say youve got the wrong no. they should send a tech out
This can not be done over the phone