Call you line provider and tell them you keep losing service, then when the technician arrives ensure the problem joint is submerged. Then insist on the line being fully replaced without joints - or if there are, in locations where they will not get wet. Keep complaining until it is done properly
Come on! Highly unlikely the engineers would have removed all of the joints. Thatís a massive job, and if the joints are fitted correctly they are all waterproof anyway.
Joints are unavoidable in the Openreach network and as Zarjaz has said, thereís reasons for them to be there.