make sure they top up the adblu in the next service, Its part of the MB service procedure. Being Pakistan you can expect them to coy you of anything.
Ive had soooo many weird experiences with shahnawaz in Karachi its simply stupid. e.g. a W210 will throw up all sorts of lights and messages when the alternator dies - they insisted that all items were infact dead and needed replacement. (the only item that was replaced was the alternator) done by me and with a used unit. Later on everything worked normal
On a second piece a W124 E320 was removed from their property by their owner as they wanted an insane amount for the repairs.
The culprit was only a failed over voltage protection relay, a bad brake light switch wire and a completely stuck EGR - according to them - it was bad ECM, a bad headgasket and a bad ASR control unit