When paying using a debit or credit card your order is activated immediately after payment confirmation. The computing power of your Mining Plan is already setup and mining. You will receive the mining accruals to your account already within the first 24 hours and afterward daily.
A BTC (Bitcoin) payment is considered complete within 6 confirmations on the Blockchain. To make sure your transaction is confirmed, make sure to include an appropriate miner's fee with your transaction. Otherwise, the transaction might not be confirmed on time.