I had the same thing happen, I emailed them and stopped my credit card from being charged constantly by the bastards. They escalated the matter and creditted me my 100 bucks about 3/4 days later.
I even got a letter from Yahoo that said I had a $100 credit but when I went to sign up it said it was only $25. This should be illegal (er... sure that'll happen)
I was reading on some blogs that Yahoo was giving out a $200 credit coupon for search marketing last year, but I don't think any of these $200 coupons are still active. The best one I could find was for a $100 credit - tried it and this one seems to work ! Here is the link I used. Let me know if it worked for you as well! EDIT: can't post a link, but you can copy this into your browser address bar to get the credit http://searchmarketing.yahoo.com/arp/sponsoredsearch_v2.php?o=US2371&cmp=Affiliate&ctv=CJ&s=A&s2=&s3=&b=25&AID=10457497&PID=2594946
I have done research and found some link below.Hope that will help you get some free bonus Free 100$ bonus coupon Yahoo Search Marketing links http://searchmarketing.yahoo.com/arp/sponsoredsearch_v2.php?o=US2314 , ok bonus 100$ http://searchmarketing.yahoo.com/arp/sponsoredsearch_v2.php?o=US2332 , ok bonus 100$ http://searchmarketing.yahoo.com/arp/sponsoredsearch_v2.php?o=US2314 , ok bonus 100$ http://searchmarketing.yahoo.com/arp/sponsoredsearch_v2.php?o=US2332 , ok bonus 100$ http://searchmarketing.yahoo.com/arp/sponsoredsearch_v2.php?o=US2238 , ok bonus 100$ http://searchmarketing.yahoo.com/arp/sponsoredsearch_v2.php?o=US2245 , ok bonus 100$ http://searchmarketing.yahoo.com/arp/sponsoredsearch_v2.php?o=US2247 , ok bonus 100$ http://searchmarketing.yahoo.com/arp/sponsoredsearch_v2.php?o=US2260 , ok bonus 100$ http://searchmarketing.yahoo.com/arp/sponsoredsearch_v2.php?o=US2276 , ok bonus 100$ http://searchmarketing.yahoo.com/arp/sponsoredsearch_v2.php?o=US2283 , ok bonus 100$ http://searchmarketing.yahoo.com/arp/sponsoredsearch_v2.php?o=US2285 , ok bonus 100$ http://searchmarketing.yahoo.com/arp/sponsoredsearch_v2.php?o=US2288 , ok bonus 100$ http://searchmarketing.yahoo.com/arp/sponsoredsearch_v2.php?o=US2295 , ok bonus 100$ http://searchmarketing.yahoo.com/arp/sponsoredsearch_v2.php?o=US2201 , ok bonus 100$ http://searchmarketing.yahoo.com/arp/sponsoredsearch_v2.php?o=US2214 , ok bonus 100$ http://searchmarketing.yahoo.com/arp/sponsoredsearch_v2.php?o=US2215 , ok bonus 100$ http://searchmarketing.yahoo.com/arp/sponsoredsearch_v2.php?o=US2106 , ok bonus 100$ http://searchmarketing.yahoo.com/arp/sponsoredsearch_v2.php?o=US2149 , ok bonus 100$ http://searchmarketing.yahoo.com/arp/sponsoredsearch_v2.php?o=US2150 , ok bonus 100$ http://searchmarketing.yahoo.com/arp/sponsoredsearch_v2.php?o=US2184 , ok bonus 100$ http://searchmarketing.yahoo.com/arp/sponsoredsearch_v2.php?o=US2185 , ok bonus 100$ http://searchmarketing.yahoo.com/arp/sponsoredsearch_v2.php?o=US2024 , ok bonus 100$ http://searchmarketing.yahoo.com/arp/sponsoredsearch_v2.php?o=US2025 , ok bonus 100$ http://searchmarketing.yahoo.com/arp/sponsoredsearch_v2.php?o=US2045 , ok bonus 100$ http://searchmarketing.yahoo.com/arp/sponsoredsearch_v2.php?o=US2300 , ok bonus 100$ http://searchmarketing.yahoo.com/arp/sponsoredsearch_v2.php?o=US2302 , ok bonus 100$ http://searchmarketing.yahoo.com/arp/sponsoredsearch_v2.php?o=US2303 , ok bonus 100$ http://searchmarketing.yahoo.com/arp/sponsoredsearch_v2.php?o=US2334 , ok bonus 100$ http://searchmarketing.yahoo.com/arp/sponsoredsearch_v2.php?o=US2344 , ok bonus 100$ http://searchmarketing.yahoo.com/arp/choose.php?o=US2258 , ok bonus 100$ http://searchmarketing.yahoo.com/arp/choose.php?o=US2245 , ok bonus 100$ http://searchmarketing.yahoo.com/arp/choose.php?o=US2295 , ok bonus 100$ http://searchmarketing.yahoo.com/arp/choose.php?o=US2283 , ok bonus 100$ http://searchmarketing.yahoo.com/arp/choose.php?o=US2300 , ok bonus 100$