Are you sure it is pex? Pex (with a few exceptions) is generally pretty resilient, and doesn't crack. It could be cpvc or some other rigid plastic pipe.
Regardless, if the leak is near the handles, have you tried taking the eschution off to try to see where the leak is? Worst case, you could make that hole bigger and use a remodel/rennovation plate to then cover up the larger hole after the fix is in.
A picture of the actual piping or listing the markings that identify it may help.
there were a few plastic pipes that had recalls and there were some pex fittings that had problems, but generally, pex has been pretty good. It could be pex, and it could be defective. If that's the case, then it may call for replacing it all, and that can get expensive. But, it is more likely one of the other types of pipe, which still could be defective and needs to be replaced.
Please try to identify the actual pipe - it should be printed on the outside of the pipe at regular intervals. Also, it would help to indicate how old the unit is.