Doesn't make much sense, but I'd try it anyway...     Create a new bid group and move existing auctions from the old one.
I'd leave the old one with auctions that have already ended with bids not placed in case the programmers want to have a go at seeing what's been wrong.
If you still haven't gotten the free snipes promised, try putting in a few 'no bid' auction numbers at http://www.auctionsniper.com/freeSnipes.aspx