That's the business you're in. If you can't compete you've got a problem, not the other guy who is willing to do it cheaper.
McDermott routinely services their I shafts with a new moori tip and a 10 point clean and inspect for $21. I've had that service and they did a rewrap on the cue because the tech noticed some small gaps. I wasn't charged for the rewrap.
Faster, better, cheaper are the mantra of the successful entrepaneur.
Like others have said. People will pay for quality service. There will always be those who will go for the lowest price, but you get what you pay for. If this "rogue cue tech" is offering a comparable service with similar quality as you are offering, you have no choice but to compete or stand pat and lose business. It's a question of how much you can fade and how long he will last.
The part about "stealing customers" I'd laugh in his face. People cannot be stolen they will spend their money on who or what they deem to be the best value.
The bottom line is that you get what you pay for. If you are overpriced you'll soon see it in your receipts.