My wages are being garnished. When I went to the courthouse to file an objection to the garnishment, I was told that I didn't have grounds to do that, and that I would have a hard time contesting the judgement because all the paperwork in my file was in line. I got copies of the paperwork I had never received, including the notice of default judgement, and proof of service for a summons to appear. The jurdgement was entered in May, the summons expired in June, I didn't receive it until July. However, according to the proof of service document, the process server certified that he personally delivered the summons to me at home in March. Under the "Acknowledgement of service" section, there is an inaccurate physical decription of me and a note that I declined to sign. The most interesting part of this document is the date and time at which the process server claims to have personally served me at my home. On that date at that time, I was at work 15 miles away, and I can prove it. Is this enough for me to object to the garnishment because "the garnishment was not properly issued or otherwise invalid?" Would the garnishment be invalid if the suit was invalid if the process server lied?

File Motion to Vacate the Judgment, for improper service, File request to Stay the garnishment until after hearing for improper service to vacate the judgment.

Look up the court rule onlin for your state.

As Mr Yet said you should be able to vacate the judgement on the grounds of improper service. Don't take the tack that it was forgery or deliberately done, because you don't have proof of that. You can show that you were never properly informed so had no chance for due process.

Now all that does is delay matters. The creditor then refiles and, if the debt is valid he gets the judgement and reinstate the garnishment.

Do you suppose the creditor might accept a settlement out of court if the default judgement is vacated?
If so, on a $7,500 suit, what is a reasonable amount for me to offer and expect them to accept?

They might. It depends on how much of that is prinicpal and how much is interest and fees. I would start with an offer of 50%, but only if you can do a lump sum. If you are talking about a payment plan go much higher.