Trai — repeated suspicious call from unknown number

Address:

282002

I am getting calls from a unknown number[protected], when i pick the call, there is recorded voice which says "goodbye" and the phone disconnects.
This has been happening for the last 3-4 days.
I am reporting it as i suspect this can be some attempt at phishing data from my phone or some other mischievous threat which can harm in some way or the other,
Please look into the matter.