Where is your company incorporated?
Ultimately, that is the key determinant of paying corporate taxes. If you are a Canadian company, you can easily set up a US$ bank account and have full merchant services via a Canadian bank or one of its subsidiaries, for example, BMO owns Harris Bank in the US.
Outsourcing "services" to another country, such as hosting or support has little to nothing to do with who/where you are obliged to pay taxes to.
Its also about what kind of taxes you are talking about: Payroll tax collection at source, business tax, collection of sales taxes ... etc..
If you are a small company in Canada, you may pay no corporate taxes if you are below a minimum income threshold.