Other members cannot help you based on your comment
Are you are a new seller on the account in question? or have not sold for some time? (if so, and as you agreed to when you listed, your funds will be on hold for 30 days)
How long has it been?
On the account you sold on, ho long ago did you last sell anything?
Has the buyer left feedback on the account in question?
Did you upload the tracking when you posted?
Did you fully and correctly sign up to Managed Payments and have been verified to start selling?
Other members can only 'guess' it is more than likely for one of the above reasons, if you want us to try to help you, you need to give us something to go on (without posting any kind of personal information)
