"Once your transaction has 1 confirmation, revisit this page and then use the form which will appear in order to wear your new membership. Your transaction will not be registered until it has 1 confirmation. Bitcoin network fees and exchange/wallet withdrawal fees will not count toward your payment."
Who will tell, I paid, but the form never appeared, after what time it appears approximately
Check the address in a block explorer. Does the transaction have at least 1 confirmation?