1. Open up a new internet window
2. Type in Google.com
3. Search for "Jury Duty _____ (whatever state the notice was issued from)
4. Click on link for said state jury duty office
5. Find info you are looking for or alternately call the phone number that is no doubt listed somewhere.
6. Problem solved.
Can't MIL read the instructions to you? She can also Fed Ex it to you and you'd have it the next day.
Is his parents address still his permanent address? If he hasn't changed it (i.e. drivers license, voter registration, etc still use that one), he is probably obligated to go. If he has changed his permanent address, likely he will just have to send in proof of his new address and will be excused.
Then I would just start calling any number you can find for any department in that county and telling them you need the phone number for the jury duty department. Keep calling numbers until someone can help you.
Call one/all your friends from back there and ask them to help you locate the info. Call your ILs back and explain that the number they gave is wrong and you NEED them to read to you exactly what the notice says. Hell I would go so far as to call the non emergency police number and see if they could help you locate the correct number.
Are you a moron? I mean come on.. you come online to a bunch of ladies who have no clue WTF you are and ask stupid questions? Please tell me you are one of this obnoxious, AW newbs.
Your MIL needs to read you the information on the summons, word for word. Plain and simple. If that cannot be accomplished then do a little research. We are not in Montana and we sure as hell can't get your DH out of jury duty. If he still lists his parents house as his residence he may be sh!t out of luck and have to go.