Dies your property line go to the middle of the alley? Is the break on your property? Alleys are typically private property with an access easement granted to the public. Call the city engineer. Citys dont work on private lines unless they broke them. Any licensed plumber should be able to do the repair. Unless lical rules require it, doubtful, you shuldnt have t relace the entire service line. Point repairs are easily doable and cost a lot less. We busted a 2" service line, in the middle of a ditch for crying out loud, and it took 8 hrs for two plumbers and cost $2000. Long story. Again, call the city engineer and get some straight poop.
Btw, a 4" service line for a small church building seems excessive. Just sayin