Phillip Phillips' family says the singer left them high and dry after winning "American Idol" -- refusing to help them out financially -- and now, they've been forced to sell their cherished family business ... So say sources

The Phillips family-owned Albany Sporting Goods and Pawn -- which has been in the family for 24 years -- is scheduled to hit the auction block on December 1st ... and we're told, Phillip's dad hopes to use the profits to cover the family's mounting debt.

We're told Phillip's dad hopes to bring in between $200,000-250,000 during the auction.

We're told Phillip's family has reached out multiple times to the singer for financial help since he hit it big, but Phil has blown them off.

No response yet from Phillip himself, so let's hope this is misinformation