Opening a vehicle door should normally not take longer than 5 minutes.
I have been working for the ADAC roadside assistance service for over 6 years now, and I know what I'm talking about.
The thing with the hammer was completely pointless. The air cushion would have been a viable option.
It might not be the control unit that's causing the problem; the car could be locking itself due to a faulty microswitch in the lock, which sends a 'lock' signal when the door slams shut. In that case, it would be a vehicle defect and covered by the manufacturer's warranty, meaning VW would have to cover the repair costs based on the invoice.
Best regards, and I hope this helps.
Sven

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