Who called from 4433820237

The phone rang twice and when I answered, no one responded and then they hung up.

Answered phone, there was a click, no one answered.

same as others , rings once or twice then stops.,  could be a scam, i just keep ignoring, and deleting it

Received call this Sun afternoon at 2:35pm. Did not answer. Do not answer unknown numbers.

This number and two others came from a call center. Stated that it was about a donation for Vietnam Vets. I cannot reach any of the numbers. They either do not answer or they hang up immediately. Scam?