There are things you can do yourself to help indicate what or where the problem may be, if you don’t normally have a phone plugged in, get one and plug it in,
Do you have you a dialtone ?, if not , report the number associated with your account as faulty, if you do have a dialtone , dial 17070 and check if the number announcement matches the number on your account.
You could call your number from another line or mobile, and if someone answers your ‘number’, then obviously your number can be used by that person to make calls that would appear on your bill, ask them politely if they have noticed any issues ( like when they make a call the wrong number appears on the display of the line they have called ) , you could also ask if they are physically close by ( in the same street for example), this may indicate where the ‘fault’ is .
If your line is crossed ( you have someone else’s number and they have yours ) but you both have the same broadband provider, then broadband would appear to be functioning OK, but obviously the telephony won’t be straight.
