2013 Ford Fiesta latches & locks problems

I have the s package, so the doors can only be locked by key or by the interior power door lock button. If the doors are locked by key (which is how I usually lock my car), and then the passenger door is unlocked first, the interior power door lock button does not operate. This is a safety problem in numerous ways: I discovered the problem when my teenage daughter wanted to sit in the car while I did grocery shopping and could not lock herself in the car (which is a safety rule I require).

On august 8th, the driver's door would not latch. The latch was replaced at the dealer ($450). On september 5th, the front passenger side door stopped latching. We called 5 local dealers before we could find one that had the part as we were told it was on national backorder. When we were able to locate a dealer with the part, we were told that it was reserved for the service department only.