Plastic wrapper "grilled" to my burger patty

I recently purchased one of Food *****s' burger specials from their Stellenbosch branch. when I bit into the one burger I discovered that the plastic wrapper hadn't been removed and was "grilled" onto the underside of the patty.

This was a very off-putting experience. I contacted the branch privately on the 23 may (the day of occurrence), but have yet to receive any feedback about this incident.