I had my parking brake pedal replaced or repaired 4 times in the last 6 months. It usually works ok for less than a month, and then the ratchet starts slipping and it won't stay down. The replacement pedal assembly has been a a Dodge part installed by an independent garage.
Has anyone heard of problems with the Dodge replacement pedal.

 

Welcome to DF

It could happen with any replacement part. I would first by checking the rear brakes for adjustments and ck the cables too.

 

Your complaint sounds familiar, I had to replace the brake pedal too.
It was a nasty job to wriggle out the old and shoehorn in the new pedal and to make it worse, the only problem with the old "bad" part was that the pawl which engages the ratchet just needed a drop of oil on its pivot. This I found out after installing the special order replacement... It was not returnable and would be a real pain to put back in the old pedal even after it was oiled.
Add to that slap in the face, the new pedal's slip tensioner (keeps from over applying the brake) tends to slip all too easily and will not engaged the brake solidly. I have to hold the brake release and repeatedly apply the parking brake until the pedal feels solid. Then I let go of the release... crappy way to have to do it.
Sometimes things just do not work out well!

Stan