Quote Originally Posted by Muirenn View Post
have you checked the rims to see if any of the spokes are poking through the rim tape? Do the rims have rim tape? But... you said there are no holes? Did you fill the tubes with air and check? Confusing.

I've had problems with valves before. And my old pump was so poorly made that it damaged valves. Barring that. Are all the pieces of your bicycle pump screwed together properly? They can loosen and cause valve issues.
+1 for spokes and rim tape. If that's the case, the shop needs to fix the wheel and rim tape and reimburse you for tubes you have gone through. Are the wheels true? What is the max PSI?