Yup ~ I do not issue invoices either cause it is just too time consuming for the 'value' it would offer to the program ~ IME it is enough that their contract indicates if they are to pay weekly, bi~weekly or monthly in advance of care of the Friday by noon the contract also indicates how much their regular payment would be based on that plan ~ if they end up with a 'credit' for some reason that would alter their regular plan I just shoot them an email reminder that you payment for X date will be Y instead due to Z reasons.

I track how much I bill and receive from each client in an Excel program and than issue an annual tax receipt with the required information according to the CRA website found below on their site ... I registered a business name so that I do not have to provide the Social Insurance Number as required and can instead supply a Business Identification Number as I am not comfortable in putting my SIN out there willy nilly as that is all is needed to steal my identity

http://www.cra-arc.gc.ca/tx/bsnss/tp...rcpts-eng.html