I love taking them back, just up the price considerably.
Everybody seems to say that on here, but unless it was under priced to begin with, why ?
Say you're a customer with virgin but sky has a deal on so you jump ship to them, 6 months down the line you're having issues or the cheap deal has ended and you want to go back to virgin but to teach you a lesson they will only take you back if they up your bill by 50%. would you accept that ?
Of course you wouldn't.
Maybe its because you don't want their business and regard them now as a messer, I take a slightly different approach that I am just one of many service providers. As my previous post we can all be fickle customers and I can never take for granted that my income as a self employed person is safe, I'd do all I can to retain my customers, even the returning ones.