Is this B2C or B2B? Large companies or small companies? Small or large payments? Recurrent billing of fixed amounts or variable amounts?
With large companies or companies which do a lot of business in USD you might possibly get away with a USD invoice. (Larger companies will typically have USD accounts as well as CAD accounts).
Otherwise a CAD invoice / payment by CAD cheque OR accept credit cards (for smaller amounts).
As a customer, it costs me/my business too much effort/money to draw a USD check on a CAD chequing account.
The best solution depends upon the nature of your business and the costs involved.
- If a lot of payments were involved, you could set up a CAD bank account.
- If it's B2C, you need to accept credit cards.
- Paypal lets you send invoices / receive payments in multiple currencies. (If it's a business account, the buyers don't have to have a Paypal account)
- If you are selling software, companies such as FastSpring will handle the currency conversions, recurrent billing (and a lot more besides).
- If the amounts are large enough and the payments infrequent enough, the cost of paying a CAD cheque into a USD account may be acceptable. (I do this in the reverse direction)