Okay gang, I just talked to the Shipshewana Campground. No problem getting through. The phones are working fine. They said to be sure that you are in a good area for cell service before you call them if you are using a cell phone, , also they are extremely busy, 60 reservations alone yesterday, so they will be glad to return your call if you would please leave them a message and a number to reach you.
If you reserve online, you won't be part of the group, so advice is to call in. I seem to be able to get a hold of them around mid afternoon most of the times I have called. Super heavy duty camping time there right now, so be patient and keep trying.