Experience letter/ salary paid in cash

[Rapri]

In my experience letter employer mentioned the salary paid monthly (XXX per month)
- is it accepted by CIC? or it should always be annual salary?

Also, my salary was paid in cash, and employer has clearly mentioned it in reference letter
- is it accepted? by the way i don't have salary slip with me. is it compulsory to provide salary slips?

thank you for help!