Same thing happened to me. No voicemail, only six digits.
They are able to spoof their number within their phone system. It obviously a bigger company to be able to have a larger phone system with a T1 DID trunks.
Its against federal law spoof your phone number like that.
Just got a call on my cellphone. I couldn't answer at the time, but I usually push 1 to get an operator and the play along giving bogus info. Just a little satisfaction to waste their time. Surely that can't be getting real carpet cleaning business from these annoying calls. It is probably some scam where they ask for your credit card number or an upfront payment. Losers. But I feel somewhat sorry for the operators working for them. Clearly they're not the sharpest knives in the drawer, but probably just happy to have job.
Same thing here. Incomplete number displayed on my cell phone. Almost all the junk calls I get on my cell phone in the last two years are from a carpet cleaner. Probably the same scammer.