Thanks for your replies Rolig Loon & LittleMe Jewell.
@ LittleMe Jewell-- I was able to (finally!) chat with the Lindens, and this is what they said:
"...It's possible that although you sold the land, you may not have decreased your contribution to the group.
That means that even though the group no longer owns that parcel, you may still be contributing your personal
tier to the group.
To check this, [go in-World] open Communicate > Groups, right-click the Group that owned the Land and choose View Info.
Then open the Land/Assets tab. Next to "Your Contribution" there will be a number where you can change how
much land you're contributing to the group. You will most likely want to subtract the size of the land you
just sold from your contribution."
And this worked!
It also reflected on my account immediately!
I haven't had this kind of good result even with my Bank! lol
Thanks again guys,
-Michelle