It would be more accurate to say that it is much less likely that phantom calls would happen on a phone line via the hub but it is not impossible. There have been past topics on here where landlines via the hub have run up phantom call charges. There have even been past topics where a conversion to a 21CV hub connection was implemented to mitigate against phantom call charges and yet the phantom calls continued.
https://community.virginmedia.com/t5/Home-Phone/Someone-is-using-my-landline-phone/td-p/4531065
https://community.virginmedia.com/t5/Home-Phone/Charged-for-calls-I-didn-t-make/m-p/4917581
https://community.virginmedia.com/t5/Home-Phone/Ghost-charges-to-international-numbers/td-p/4967252
https://community.virginmedia.com/t5/Home-Phone/Phantom-call-charge/m-p/5124250
https://community.virginmedia.com/t5/Home-Phone/Charged-for-unmade-calls/m-p/5141979
https://community.virginmedia.com/t5/Home-Phone/Ghost-call-charges-again/td-p/5192333
A further 3 topics (where a 21CV connection was used) are in the forum archive
https://community.virginmedia.com/t5/Home-Phone/Getting-charged-for-phone-calls-I-have-never-made-as-there-is/td-p/4406247
https://community.virginmedia.com/t5/Home-Phone/I-ve-been-charged-for-calls-that-I-didn-t-make/td-p/4414274
https://community.virginmedia.com/t5/Home-Phone/charged-for-numbers-I-haven-t-rung/td-p/4416584
@MrsEileenS
If you are experiencing phantom call charges, they typically follow certain patterns. You may find calls of very short of very long duration or repeating calls which are an exact number of minutes. Calls may happen at unusual times of day and night (when no one would normally make a call). Some calls are to local numbers or a particular dialling code along with a random sequence of numbers after the dialling code.
We have also seen some kind of scam/fraud charging taking place in the past on here but IIRC that was to do with premium rate 09 numbers.
We have also seen cases where certain items of equipment in the home have run up unexpected call charges when they 'phone home' to a call centre etc. (such as some call blocker devices and security/care alarms). If you have anything like that connected to your line you may want to investigate those.