Jei & Bill with SUPER late computer

Dear Sally Albright,

We are going to take part in technology convention in Las Vegas. As I am not sure when you will get back to your office, so I would be grateful if you could send me the copy of your itinerary. Actually, we sent you the brochure about coming this conference, but we didn't receive your reply, even though you would have sent us due on April 7th.
If you have sent us the reply aleady, we might miss tthe reply.
Could you please send me your reply again?

Best regards,

______________

Dear Sally Albright,(She is your business partner, so you don't need her last name)

We are going to take part in a technology convention in Las Vegas (Why are you mentioning this? She's going, so she already knows). As I am not sure when you will get back to your office, so I would be grateful if you could send me the (a) copy of your itinerary. Actually, we sent you the (new) brochure about coming this (for the) conference , but we didn't (haven't) received your reply yet, even though you would (should) have sent us due on (something by) April 7th.
If you have sent us the reply aleady, we might (have) missed tthe reply (it).
(If you did it already, could) Could you please send me your reply again?

Best regards,

Jonathon's message:
1. Dudes! I'm really sorry you got stuck with that lousy computer. I'm sure you would have finished the assignment much more comprehensively if you had been given one that worked.
2. You've got the right idea for the assignment, but most of your difficulties are simply grammar mistakes. Good use of the target language, though. Thanks.