refund of the cancellation amount

I have paid money for publication of advertisement to change the name of my daughter. there were no conditions in the beginning. they asked me to upload the valid document for the proof. i submitted 10 the class certificate of her. then the money was paid by credit card. when the invoice generated, i did not find the advertisement on that specific day, which i requested for release. when i called them, they mentioned, the document i uploaded is not correct and i need to to upload notarized affidavit. i told them to cancel and refund the money. After persistent follow up they mentioned that they have to deduct 25%. I looked at the website and did not find the clause of cancellation charges. when i called them, they told me to look in the invoice, where below it talks about cancellation charges 25% if we wish to cancel the ad for release for any reason. Now this clause of cancellation charges have to be mentioned upfront rather than informing me after the fact. please advise how should i proceed further.