hi, i'll be happy to help you in anyway i can.
sorry to hear of your misfortune :(
yes, pretty simple, your tailgate latch has failed.
if your handy with tools you can change it yourself.
its a relatively inexpensive part by mercedes standards.
So, how do I start????
Do I need to buy a part before I start??? and what is INEXPENSIVE by mercedes standards ...LOL?
pull of the tailgate panel and unbolt the latch, you'll need some torx bits.
$125 more or less for the latch.
So what you are saying is that I need a mechanic and parts to fix. This really isn't much help!