Had it with my kids dad's sisters! (Venting)

My 2 oldest kids dad passed away a few years ago about 4 days before christmas. We were together 9 years so I have been trying to continue a relationship with his family even after I started dating another man. Over the summer I agreed to let my kids go down to their aunt and uncles for a few weeks and they were supposed to bring them back. They got a hold of me the day before to tell me that they couldn't bring them back on the day agreed. My fiance was working and I had no gas to get them. It was going into the week before school started and the day agreed was the latest they could stay. After an argument and borrowing money from my father-in-law I drove almost 3 hours round trip to pick them up. They couldn't even meet me half way. Wanted to keep them a few days more. I was so upset I decided that my kids would not go down there for a awhile. My kids are 10 and 5. I have had it with my kids dad's sisters. They get upset and told my kids they can't call my fiance daddy (which was my kids choice to do so), they have referred to me as trash because I have not given them his ashes (which they've had plenty of chances before I moved. They even took some of his other stuff before I moved but didn't take them) I've only told them once that they couldn't have them because they wanted to bury them and I suggested doing something different with them, I've been called a grinch because I didn't give his oldest daughter her Christmas gift til about a week after it was delivered to my house the day before Christmas (this was when he passed away), they claim I keep my kids from them but the only time they ask to see them is Thanksgiving, Christmas, and Easter. They only ask how the kids are when they want the kids, they haven't been to their birthday party in a few years. My oldest 8th birthday they said they would come. My oldest was excited. Couldn't get a hold of anyone. We waited about an hour before I decided to start the party. They never showed up. My oldest was disappointed. I'm just trying to include all 3 families in my 2 oldest kids life. Sorry it's long.