Perhaps the BT rep could have explained 'potential charges' better, but if you are confident your phone is fault free ( and you have bought a new one to be certain ) and you have it plugged directly into the master socket test port and it still doesn't ring when an incoming call is received you dont need to worry about a charge being raised.
I cannot understand your reluctance to report the problem...BT ( as would every other provider ) has explained that the potential for a charge exists if you make frivolous fault report, you have a 'bell not ringing' BNR, problem ( that is sometimes not detectable using the normal line testing facility's ) , you have proved as far a practical that the problem is not your responsibility, so the 'fix' will be included in the line rental charge (free) ...but you need to 'report' it , and to progress a fault, your provider needs you need to accept the potential for charges, you seem to want a guarantee that a charge won't be raised, but they don't know if you have done any checks or not , and if would hadn't , and the fault was on your equipment or wiring, then you wouldn't be able to argue later that you didn't know about the charge if they told you in advance....you have done the checks, so why worry ?
