First-BTC is an automatic exchange service. The exchanger looks for the transaction you made in the mempool within 30 minutes after the creation of the application. You do not need to inform us in any way that you have made a payment. Your transaction will be found and the payment pending page will automatically refresh.
In the case when the payment was received after the cancellation of the application due to timeout, you need to wait until you receive a confirmation of the transaction from the network. Next, you should apply for our support by writing a request to [email protected] or by clicking on the icon in the lower right corner of the site.