i bought ptc ad,got approved and assigned.but how my account will be credited

Ad credits are ad packs that you purchase to advertise your website, product or service to our members. They are NOT used for you to see more ads and you do not make money off purchasing ad credits.

Go to Manage My PTC Advertising and there you will see your ad credits listed. You can then choose to assign them to your ad.
Here is a tutorial - How to advertise using ad credits? | ClixSense Forum

doctorjitu1 wrote: i bought ptc ad,got approved and assigned.but how my account will be credited

In this case you may want to get your money back which you have spent on buying the Ad credits . try sending a support ticket unless you want to advertise any of your other Ptc site's link/blog or website with the Ad credits which you have bought.

its may be good