It depends on what the issue is, if you have lost service because of this , you contact your supplier, if it’s a safety or similar issue ( in other words you are acting as a concerned member of the public ) then you can ( as already stated ) contact Openreach directly
If you contact OR , when it should have been your a provider, and OR turn up on the basis of a ‘safety’ call out, they could just make the cable ‘safe’ and not actually repair or replace it, meaning you then have to report it ‘correctly’ to your provider , obviously delaying the fix.....it’s not guaranteed that OR wouldn’t actually fix the issue on the safety call out , but IMHO not with the risk not contacting your provider if it’s just you affected.
