Delivery Fee

I called silkair today to check with them how could I make purchase. They said I could fill up the purchase order and then they would have it delivered to me. Or I could take their flight again within this half an year and bought on flight. I told them it's not very likely I could make it within such a short time frame. So I asked them how much it will cost to have it delivered to my house. They said S$15/piece. I told them it's not flexible in this case, because the voucher itself was only US$30, then almost half must be used for delivery fee, it did not show much of your goodwill. I hope whether this delivery fee could be waived. After a short discussion, they agreed. I think silkair is really a world class carrier.