Depends on which state, some states will not require an answer from the small claim defendant so that it is not necessary that the defendant serves you his answer if he files one.
Relying on one technical error, even though I would think is serious, is dangerous since if the judge ignores it, the order is final and you have no recourse afterwards.
Regarding motion to set aside, in some states you can only file motion to set aside if the order is default. In your case you probably cannot even file one since you lost in court.
