相談先はCRA (Canada Revenue Agency)です。
http://www.cra-arc.gc.ca/tx/ndvdls/tpcs/ncm-tx/rtrn/cmpltng/slps/menu-eng.html
What if you do not have your slip?
If you have to file a return for 2015, file it on time even if some slips or receipts are missing.
If you know you will not be able to get a slip on time to file your return, or you do not receive them, and you are registered for the CRA My Account for Individuals service, you may be able to view your tax information online. Otherwise, attach a note to your paper return stating the payer's name and address, the type of income involved, and what you are doing to get the slip. Use your pay stubs or statements to estimate the income to report and any related deductions and credits you can claim. Attach the pay stubs or statements to your paper return. If you are filing electronically, keep all of your documents in case we ask to see them at a later date.