Hi Abdul Latif, be sure that if anyone has used a voucher once he can't use it any more or he can's sell it to other to use it again. And if the a voucher has become out-of-date after one year(think you have baught a voucher at 01-07-2000 then it will expire at 01-07-2001,AFAIK) then its no more usable.
Yes vouchers are transferrable as they do not contain any name and may be used only once by anyone....but then
you should contact your nearest Sylvan Prometric
Testing Center to clarify that you have paid for other one's voucher and give his name and other details.
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Muhammad Ashikuzzaman (Fahim)
Sun Certified Programmer for the Java� 2 Platform
--When you learn something, learn it by heart!