It's a scammer. This number was SPOOFED on the caller ID hence the reason you couldn't call back. Best not to call scam numbers back in the first place since they can get your number.
Have called about 5 times in past few weeks. Now blocked.
I don't really get the logic of "don't call back because they'll get your number". That's because,
1) they already "got my number" and know it's a valid number since it didn't give them a not in service recording.
2) their machine is probably calling random sequential numbers using a given area code and prefix and it doesn't care if it's a valid number or not, it calls all the numbers in that particular sequence starting with numbers ending -0000 and going to -9999. Doesn't cost them a penny to call bad numbers, blocked numbers, cranky old men (like me), etc, etc.
I've had this number blocked for more than a few weeks now; it's a spoofed number and every time I think I can delete it from my call block list it pops up again. It's gotten to the point that about every 2-3 weeks I have to cull through my landline block list or I reach the 250 limit.