Wrong: "Na-sent ko na sa 'yo."

Correct: "Na-send ko na sa 'yo."

The prefix "na" already indicates past tense, while "send" is not an indication of present tense but is, rather, a truncation of the infinitive "to send".

Wrong: "Na-missed kita."

Correct: "Na-miss kita."

Correct: "Na-get ko na."