What car have you got currently as some are 12 months or x miles and others 24 months x miles for service schedules ?
Never nown Mb wanting a car serviced before its sent back. The only other thing I can think of, your current car was due to be delvered in April but, didn’t arrive untill June and that side of the system hasn’t been updated.
Ring the dealer you had it from and clarify when the serice is due and then speak to Mb.