Torchwood Anatra

I am confused. After owning my land for 5 years, I was away for a month and came back and found my land had been taken by the lindens, all my things were still on the land, but it was not set to Dee Linden. I found a email in spam that said my group donations were over and I needed to correct. Which I didn't while I was gone, so they took all the land. I had 3 groups on two sims. 2 parcels were on on sim, and 1 parcel was on another. No other changes that I was aware of. I have a 1/3 region total land holdings, and my teir fee had not changed. But I am confused what has happened? And how I make sure it does not happen again. I rebought the land from Lindens, and then deeded the land to two groups. Instead of 3. But when I go to my land info, it shows my holdings in land fees, but says I do not own mainland. In group land it shows what I donated to the two groups, but it does not equal the amount of land I own. I am so confused! I don't want to mess up again and I never had a problem before. Not over prims. Not sure about the group credits either. Below is the email. "You are being contacted because you are the owner of one or more groups that are over tier. The group owned land exceeds the Second Life land use fees. You, or another member of the group, must increase the land contribution to support the land that is currently owned. If you do not wish to do this, the group land holdings must be reduced." Can someone please help explain what I need to do or not do?