It may not be all doom and gloom.
Contrary to pub gossip, the actuator (robot) is actually a pretty reliable thing, sometimes let down by crummy FIAT wiring and conectors, more often by inept use or incompetent diagnosis.
First assumption: it does not leak.
Second assumption: no "experts" have touched it
Third assumption: it works fine in manual mode, but seems unsure about gearchanges in auto mode.
If all 3 are Yes then:
1. Check the tailgate wiring (search the forum for 500 tailgate wiring, doesn't apply to Pandas)
2. Check your brake lights work properly. If not, fix that problem, as the ECU does not understand what you are doing.
3. Check the connectors on the rear lights, as corroded terminals can confuse the ECU.
4. Get your Gearbox ECU codes read. For this you need a FIAT dealer, or
MultiECUScan registered version and appropriate cables.
If still no joy, report back and we can try some more.
If any of the assumptions are No, sorry, you're looking at a (un)reasonable bill.