Caller left a message that they were calling in regards to my health insurance (Aetna)

It is for Life Master's, It is a supplemental Health Insurance that goes with you're existing plan....Like if you have a chronic illness'. they help pay for other medical needs your Insurance does not cover.

how can I reject this call?

I get 1 or two calls a day. Never leaves a message.

I missed two calls from this number. Didn't try to call back because no message was left.