how to remove adfly advertisement

how to remove adfly link
its very frustrating for forum members
they complained alot

Where do you get this adfly link?

when i post any link on forum
for example : http://depositfiles.com/files/vpd3dw6ye
when forum members open this will change to this :
http://adf.ly/246619/http://depositfiles.com/files/0h779via7

You have to pay for the removal of forum adverts as this links on to forums who have not paid for no adverts

Links to the most popular host sites (like Mediafire) will cause the adfly page. Using credits will not remove it.

how much can i pay for this
and tell me how much i pay to change domain www.gsmhum.com

As SlGray said you cannot pay for it.
For buying a custom domain name, it costs 1600 credits which books the domain name for a year.
Check it in your admin panel.
Misc>Spend Credits
Domain name
Check how much is it for 1600 credits.

The ad fly comes from the upload host, it has nothing to do with your forum.
In order to remove it, you must pay for a "gold" or however is called account at the host you use.
For support on this issue you should contact the file host or you can just change the host and use another free one instead of depositfiles.

If you have small files, like the one you show in the link, you can activate the Attachments and use credits for more space.
https://help.forumotion.com/t66572-attachments
Your files will be uploaded directly in the forum's database and you won't see any advertising on download.

As said above, forumotion can do nothing about the ads coming from other sites. While I find some of the image from forumotion ads to be a little annoying, forumotion generally isn't nearly as bad as mediafire about the ads in general, so forumotion really isn't the source of the problem.

Have you considered using dropbox instead of mediafire for hosting uploads? Mediafire is absolutely insane with the ads, but dropbox seems to be more reasonable about all of that.