Blocker and auto mail thru "MS outlook"

My sales team member is assigned to each customer for 3 succeeding years from the date we sign-up a new customer. Say I sign-up new customer on Aug. 28, 2014, my sales team member is responsible for that customer until the end of 2017 i.e. Dec. 31, 2017 (3 succeeding year after SignUp). I will As soon as time up my team member is no longer required to serve.

I wanted to have –
1. A blocker statement ( maybe I’ll do some conditional formatting too) which says “you should not work on this customer”
2. On the contract end date with a customer, I would like to send an automatic mail saying, “your contract ends …..”
I created a sample worksheet to explain what I am expecting –
1. Cell B1 shows today’s date, so whenever I open the file it will pick up that date and process further.
2. Col. C is dated when we sigh-up customer
3. Col. D is customer mailed 9 all are sample IDs as I cannot use real ID )
4. Col. E explains the condition which I needed
5. Col. F is sample date (manually entered< I tried to create formula which you can see on col. I, but I don’t know how to get the calendar year right)
6. Col G & H shows another formula which I needed and which I think I got it as well (suggest me if there is a better way)

Any answers to this query?

Come on folks! I know there are many wiser than me