Well, even though the service rules were not followed, you have actual notice of the hearing, so you should attend (unless it is less than 15 days away, in which case you should call the court and ask to postpone it because the service of process rules were not followed).
The service of process rules will protect you if you did not appear, and later asked to set aside the judgment because you were not served. But it won't get the case dismissed outright or anything.
At this point, it really won't help you to avoid court, even though you were improperly served.
Like you said, the rules are in place for a reason, but that reason is to make sure that you are aware of the court date, which you are. If they took a default judgment because you never knew about the hearing, you could get it set aside because of improper service.
But at this point, it is probably best to just appear or contact the lawyer on the papers and try to settle it.