I remember your previous posts here and your dealer is telling you the truth. If Vadis can't communicate with a specific module and they've tryed the few little tricks to wake it up as any tech hot line guy would suggest when called, THEN there's no other alternative but to replace that module with new SW. I've seen and heard of a couple bad REMs too but it's not common.
As for other new electrical problems since then, again they're right as with Volvo new (less than ideal) networked technolgy, when one part of that network fails or is unplugged, other new, unrelated but temporary electrical problems (messages, warnings) often show up until the main problem is cured.