Sudden Increase In Call Charges

[#1]

If that was a call from him, direct to your mobile then I would agree! and I don't see how such a call could appear on your landline call list. If you check the call history on your mobile , does that call show as from your own landline number or from your sons mobile number ?

[#2]

Something is terribly confused here - an INBOUND call's to the Plusnet land line number will not appear anywhere on a Plusnet bill.

If there is (on no answer) call diversion on the landline to the mobile then...

1. If the telephone hand set records the CLI of the last N callers, the calling number will show on the handset
2. The call  to the landline will be diverted (on no answer) to the mobile and show as a call to the mobile on the Plusnet bill
3. The mobile receiving that call will see the calling number (not that of the house phone) so the receiver will have no knowledge if they were called direct or are receiving a diverted call
4. If the diversion is to a mobile number, that could give rise to a charge, even if the call does not connect / is not answered / is answered by voice mail

"The 8 minute call was to my mobile from my son's mobile."

How do you know that the call was from your son?  The calling number would not appear on your Plusnet bill.

[#3]

@BobR1 A very long shot, but could your son/someone else have used your home phone by mistake rather than their mobile? It happened here, only twigged when we received a monstrous bill for one call between my dear wife and her sister   and some important matter or other 🙄

But then we're still getting used to the absence of Buttons A and B.

Mike

[#4]

@Townman

I know because I asked him.

@Longliner

There was nobody in my own home to pick up the wrong handset.

[#5]

Hi @BobR1 

I've been going through your account to see if there's anything there that might be causing you issues. Short answer is no to be honest, the only conclusion I can find is that the call has been made from the landline. 

Also, I've ran tests on the line, nothing comes up there either. No products on your account that would divert your call, even if you did you would've set this up yourself so you'd be fully aware this would happen. 

There is no way a mobile would ring you and then we charge your landline for that. I really am stumped to found another explanation other than the number was dialed for the phone.