Never leave a message and call from a similar number hours later, if the number is not in my phone and you do not leave a message I will Not answer and I will not call you back!
If this is legitimate then they would have left a message the first time. It is curiosity that kills the cat.

indian accent call centre talking about hot water service rebate

Missed call back the number is not in service in American accent

They called twice and didn’t not leave a message. I called the number back and it doesn’t not connect. it says the number dialled is not in service, please check the number and try again.

Call dropped after a few seconds. Imagine it was a telemarketer or other SPAM.

Did not leave a message