Who called from 5407654405

This person keeps calling me & hanging up

Got a message to call Mrs Nelson at this number. No other information given. I refuse to call.

When I answered a recorded male voice said
"Hello.  This is an important call of a personal matter.  Please stay on the line for the next available representative."
I held for 30 seconds, then the same voice asked me to keep holding and told me to press 1 if I wanted to do that.  It seemed like a bad idea, so I hung up.

A Mrs. Nelson keeps calling my home during the day and leaves a message for me to call her back.  I've tried to call back and the phone just keeps ringing and ringing.  I'm going to block this number from my phone.  Who is this person?  Any ideas?

Possible from Freedom First Credit Union-Credit Card Unit