2004 Citroen C2 VTR Sensodrive review from Sweden

Two major similar incidents have happened recently.

When pressing down the gas pedal to accelerate, the car when starting from stand-still at a traffic light, the car accelerated by itself, increasing the gas and changing to higher gears. The car acted as if the cruise control was set at a high velocity, and the car itself tried to accelerate up to the target velocity. Worse was that it did not help to brake, and the only way to stop the car was (as I saw it) to pull out the ignition key whilst braking hard with both the foot and hand brake, so that the engine stopped. Luckily, the steering wheel had not locked, I assume because the brakes were on full.

Now, the car is at the Citroen mechanic. The mechanic has upgraded the software, but tells me that I have probably obstructed the gas pedal with the mat - but I know for sure that this is not the case. My plan is now to get the mechanic to go with me on a test drive, to test that the same thing does not happen again. Hopefully, the software upgrade has had an effect, regardless of what the Citroen mechanic says. I am concerned that there may be other cars with the same software and gas/gearbox system that may have the same problem.

Has anyone else with a Sensodrive system (C2 or C3 or other) from the same production years had the same or similar issues?