Find a car locksmith in your area - he will have an airbag device to pump up and create a small gap between glass and door - then use a hook to unlock the door. He will also be able to remove the panel and possibly diagnose the unlocking problem.
Amazon sell this for £15
MICG Rubber Auto Entry Airbag Powerful Hand Pump Locksmith Tools Car Door Opener
Good Luck..., February 2017