Maybe or maybe not?

I am just wondering if a person you know does not response to your email many times for a while. Maybe that person does not want to keep contact with you or maybe not?

For example:

Sending an email to that person on Feb 27 to discuss some issues s/he mentioned
No response, sending another email on March 15 to discuss.
No response, sending another email on March 23 with more topics and information to discuss.
Still no response. What would you do?

The worst part is that this similar situation has happened many many times in the past 5 years. It just makes me feel this is a one-way export but not two-way communication. Truly and really frustrated.