Training help! I'm at my wits end! [x-post /r/austrialiancattledog

I have a one year old cattle dog. She is the light of mine and my husband's life. We went to training classes when she was around 9 months old and she graduated with flying colors. Although lately she refuses to listen to commands. Our biggest issue is coming on command. We love to bring her to the dog park when we're feeling to lazy for hours of fetch, but when it's time to leave it's a big game of keep-away. It takes us over an hour sometimes to catch her, with the help of other people (sometimes 10 of us trying) Just wondering if anyone has any advice on how to retrain my stubborn dog.

Also, we have a 30 foot leash that when she's on she comes on command just fine. It really is just at the dog park and occasionally when she doesn't want to come in the house.