Welcome to Justanswer.com, my name is Dustin.I'm sorry to hear about the issue you are having, I will do my best to help you resolve it.
The upgrade to 10 and downgrade to windows 7 probably damaged your outlook database or permissions.
Also, would you like me to connect to your computer from here and work on the issue directly on screen? If so we can set this up via a secure remote assistance session. That session is guaranteed meaning if I cant help you then you will be entitled to a full refund of all fees.Otherwise, I can try and assist you via written support alone. Let me know how you'd like to begin.
Dustin S.Senior Technician and Network Switching Systems Operator / Maintainer.
I sent the offer at a reduced cost, on my end it said payment failure when you tried to accept.
This sometimes happens if your bank or credit card blocks the transaction and a quick call normally clears that up.
In the meantime I will send the offer back to you to be clicked and approved when you are ready.