I bought a ticket to a charity event for $4,000, ded. portion is $3,500. I then donated ticket to another charity for their use. is my total dedauction 7,500?

No, your maximum donation value can never be more than your basis (what you paid) so $4000.

If you report it as a $3500 donation to charity A, then only the remaining value of $500 is a donation to charity B.  You can't get a double deduction.