If I were you, I would book a small order as a trial.
If I were in your position, I would allow partial shipment.
Why not buy a small lot and put them on trial?
Why don't you look at it this way? It's more expensive, but much better value for money?
I'd advise you to look into the matter immediately.
I think you'd better weigh up the advantages carefully before rejecting our offer.
I don't think you should miss this opportunity to update your equipment.
After you have tried it out, I'm sure you'll agree that this is a very good product.
I can't force you to make a deal, but I can assure you that our product has the edge on the competition.
You're right to be cautious, buy owing to the limited supply available at present, we suggest you act quickly.
I don't want to sound pushy, but you'll have to decide soon.
Do you understand that this offer is only open for three days?
I understand your concerns, but remember that the offer ends next week.
You may trust me that any money spent now will bring you big profits in future.
Could you think about our proposal again?
Could you reconsider the matter in some other light / from a different angle?
Isn't there any way to change your decision?