Buying aluminium ingots, 200 tons required every two months

We would like to buy aluminium ingots A7.
Need 200 tons every two months.
Regarding the payment method, we only work with deferred payment covered by credit insurance for a period of 30 days net.
However, for new suppliers, we offer a payment term of 7 or 14 days net.
Additional costs (credit insurance costs and DDP delivery costs) will be borne by us and may be added to our final invoice.
Thank you in advance for your understanding and your usual responsiveness.