Openreach aren't allowed to talk to end customers - it's not a matter of them not wanting to. That was a decision taken back when the whole thing was set up, by the telcos who use Openreach's services.
There were I recall several options under consideration, one of which was where the line was rented from Openreach by the customer and then they bought services from providers over the top. It was rejected by industry and Openreach were forbidden from talking to anyone other than the telco as a result. I think there was a reasonable fear that customers would insist Openreach visit their site, but if the visit resulted in chargeable work - for instance where a customer had damage something - that Openreach had no mechanism to raise that charge with the customer and would charge the telco instead for something they hadn't asked for.