After the purchase contract become effective, the purchaser should ide should remit the payment to the designated bank account of the supplier in accordance with the payment terms in the contact. Only when the payment is fully accepted, it deems to be a account credential.
The purchaser fails to arrange the payment as the agreed payment terms, the supplier may charge the purchaser 0.03% of the amount per day for overdue payment. If the supplier has not received full payment of the purchase contract within 8 weeks of the deadline under the purchase contract, the supplier is entitled to the immediate terminate the purchase contract, and no need to assume any liability for breach of the contract.
The supplier could issue the VAT invoice after customs clearance of goods, and mail the invoice to the purchaser by express.