You should use the simple present tense when you are talking about something that is happening now.
"Knew" is the past tense of "know." In the present tense, you would use "know" instead. For example: "I know the answer."
You should use present tense.
Usage of Past Tense or Present Tense is all depends on the topic.
I believe the correct tense you would use is present tense.
The present tense
First of all, the question should be: "Should you use the past or present tense after 'never'?"The answer is: you can use any tense after 'never'. It depends on what time frame to which you are referring.
When discussing your own ideas, use the present tense. When discussing the ideas of another person, use past or present tense depending on whether the idea is still relevant.
To discuss your own ideas, use the present tense. When discussing someone else's ideas, use the past tense.
the present tense
"is' is present tense. For past tense use was or were.
The present tense of the verb "use" is "uses" for third person singular (he, she, it) and "use" for all other subjects (I, you, we, they).
They are used in the present tense. So, you should use them when you are talking about something arising at the present time.