If you pay your invoice or payment invitation online (using Bancontact, Visa, MasterCard, ...) the payment is processed within 10 minutes. When paying with bank transfer, it takes longer: up to five working days.
Check the structured notification on your invoice or payment invitation. A payment with an incorrect structured notification might not get processed. If that happens, it is automatically refunded to you.
Also make sure that the amount paid is exactly the invoice amount. Even one cent more or less can cause difficulties.
