Can I enter estimated t4 values if I believe the ones my employer gave are inaccurate?

I have gone back and forth with my employer as I believe the numbers that are on my T4 slips for employment income are incorrect. They have told me they are looking into it but I have not heard back in over a month and can not wait anymore. Am I able to enter the values for my employment income according to what is on my pay stub instead of what is on the T4?