His round isnt worthless.
I would buy it for a nominal amount (Very small amount). Then I would walk the round, tell each and every customer that you are taking over but the new price would be £...... whatever it needs to be.
Explain to the customers about the pricing, I am absolutely positive about 80 % will sympathise and pay the new rate straight away, those who wont arent worth having anyway..
It has got to be worth a punt, get the customers at your prices, then you are onto a winner.