I have same experience for 100. 80 and 40% coupons. These coupons really does not work. Every time my efforts ended with the computer screen of "server unavailable" or "Coupon not active" or "Time expired".
How can "coupon not active" can come? then why coupon posted on site?
But, in all this coupons of 20 & 10% works very fine.
This promotional offer is fake and cheating with customer.
Ebay has good reputation so this type of cheap ideas are not required.