I'm assuming from the way you asked that the service cable in the pic is the Pepco side so I would call 202-872-2000 for the corporate office / contractor / city services line. Pepco has their own dedicated commercial / residential service inspectors and will charge $480 to turn the power off at the pole. They will then reconnect after the contractor has supplied a new service cable to the rainhead.
Unfortunately, in DC, the quality of workmanship is the lowest in the nation. I have never seen them fail for wrong connectors or cracked SER/SEU/SE, but I just had to repair one last week that was not only cracked but was hanging directly over a window. Both the county and Pepco passed it (bank paid for heavy up) but it was on an investment property I was going to move tenants into so I fixed it anyway... Pepco has smart meters in now so they don't like contractors pulling the meters anymore, but they don't charge for a service truck to pull a meter. They do want 3 days notice, no charge.
DC proper does have a lot of underground buried services so if the feed is coming from the other side, I would really like to see a picture of the inside to see how the feeders are routed.
Just because the county/city approves it, doesn't mean the Pepco service inspector has too... but they often will skip their own inspection to save manpower. The Pepco service inspector is the one who releases the work order to construction to connect the pole / rainhead / underground feed.
In this area most of the work orders are now filled by subcontractors from South Carolina who drive home on weekends. I have seen them "fix" a connector like the one you posted by cramming it full of duct seal and calling it a day. Are those open knockouts in the top or dirt?
My heart goes out to you for trying to get them to do the right thing, and I very much do hope that you are able to make headway.