Is a repair bill from Schifrin, Gagnon & Dickey for a cut cable legitimate?

I cut the cable (that was buried about 3 inches deep btw) planting a flower.  The tech fixed it uneventfully.  Six months later I received a letter from "Schifrin, Gagnon & Dickey" with a bill.  The letter looks like a scam to be honest.  Also (suspiciously in my mind), they say they are "willing to discuss resolving this matter for a lesser amount" but don't say what the lesser amount is. 

So is it real, and if so, what's the deal with the "lesser amount" offer?