Have you sent her an invoice for the items she wants to buy (with discounted combined shipping)?
I mean, she's interested enough to contact you...
Wouldn't that be faster?
Then you can solve the cart problem at your leisure.
Oh, also, do you list only on dotCA or are some of your listings on dotCOM? And do you list exclusively in USD or in CDN? Or do you mix those depending on the item or the site?
Because those won't go into a cart either.