Was trying to ring a friend who has fallen foul of the 'Windows Security Centre' scamto find the result of a scan I asked for and now her phone line is down! Co-incidence, I assume, since I can see no logical link on a BT landline. However, I don't think they have 'enabled' her mobile for use free - this always used to be the action. Has that changed now?
Indeed - just a coincidence.
When a line is faulty BT Retail will divert incoming calls to a mobile 'phone if requested (it's not pro-actively offered unless the customer is obviously vulnerable). In all cases the customer must quote their BT account number to set up the call diversion.
Alternatively, you can visit www.bt.com/faults, enter the 'phone number and BT account number and set the diversion up yourself.
The only time this will not work is if the fault is at the telephone exchange because if the exchange equipment is faulty then the diversion will not work.
The reason for not pro-actively offering a call divert and insisting that the BT account number is quoted is to prevent cases of fraud. Ne'er-do-wells often falsely reported faults on an innocent party's line and got calls diverted to a mobile 'phone in order to facilitate criminal activities which I shall not discuss here!