Thanks for the replies...I wasn't really considering taking action based on this, but wondered how common this practice was. I get that the other party wants to make sure I have received their filings/motions and don't pretend to be a civil procedure expert, but seems like RESPONDING to a motion provides proof that I received it. Of course, in the case of the amended motions with different dates, my response to the one I received in the mail would not necessarily mean I received a copy of the one that was filed with the court with a different date.

@LexisLutor might be right that there was some delay from the time the creditor requested that the Sheriff serve me and the time it actually took place. However, at least with the original motion, the Sheriff contacted them AFTER they had received my reply (and I believe after the Judge had set a hearing date) to see if they still wanted him to serve me and they said yes.