It's disrespectful not to answer the phone or text messages.

Yes Very disrespectful. The feelings between people are actually very fragile. Take good care of it. If you are a friend or colleague, you must answer the phone, even if you don't answer it, you must go back. Explain why. People who know each other well can be another matter. You don't know him very well, depending on whether you want to continue dating him or not. If you want to, you must go back.