I get my broadband and home phone from plusnet who advise me they are 'part of BT'. My internet connection is intermittent but I have had no home phone for 4 weeks and we are also in a poor area for mobile phones. Plusnet put the blame firmly onto BT openreach engineers who appear to be non commital when the variety of reasons they have given will allow them to re-connect my phone.
I have an elderly mother who lives 300 miles from me and will only call me on landlines because she fears the cost of calling mobiles. My partner is a musician and relies largely on the landline for business calls.