Everything is replaceable, even me!
If I decide to only work 2 hours a day, and I'm no longer able to keep up with the tasks delegated, I'll be replaced.
On the other hand, if I can get all the work done in the 2 hour time frame, then more power to me!
If you're not happy with performance for any reason, then you need to evaluate your options. If that means paying more, or using a different center, then that's the options you have. Of course, it could always be bad programming too