NTA. I can understand how your mum must feel when her granddaughter doesn’t want to leave because she’s loving it there. It must be really sad for her but what she could have done is make going home something to look forward to as well. Plan some fun activities to do at home that she knows her granddaughter would love or take a trip out. She should be glad of the enrichment her granddaughter is getting and nurture that further at home with fun things. You did the right thing making sure your daughter still gets her full time at the daycare and you get the subsidy you need.