I think I've posted these in similar threads
When we were kids we started getting these weird all hours phone calls. Dad figured out it was independent truckers looking for jobs to haul back to their home bases. He got one to stay on the line long enough to find out they were calling from a truck stop in Katy, Texas. (Which hadn't been swallowed up by Houston yet). It was apparently some type of automated system that called numbers of places that needed this service in rotation. Our number had gotten into the system by mistake. Dad ended up having to take our phone bill out to the truck stop for them to get the number out of the system.
Not a wrong number but the wrong way to call and Career Darwinism thrown in. Sis and I were home alone one evening and the alarm company called for Dad's job. I told them that Dad wasn't available and that they should call Mr. T or Mr. P (worked under Dad) Well the person started cursing me out that Mr. T wasn't home and some (ugly word for a woman) was giving them the same Mr. P wasn't available (more ugly words) That I had better put my (bunch of curse words ) father on the line.
I'm thinking ok it is Friday night how does this idiot not know my parents can't come to the phone right now is code for I'm home alone. (Their jobs required them to eat out 2 - 3 times a week to maintain good relations with the customers). So I tell him to call Mr. F (man above Dad or the owner). I get cursed out. So I hang up then take the phone off the hook. I get Dad's address book and look up Mr. F's number. I hang up then pick up and dial Mr. F. I tell him I'm sorry but someone saying they are a the alarm company and was cursing me out because Dad wasn't home. He was so angry at the company. From what I heard later - heads rolled at the alarm company. It was a serious call some young teens has seen the kegs sitting in the truck yard of the business. They had gotten a ladder and managed to scrabble over the wall dropped down inside (without a ladder) and were injured. Oh and the kegs they saw empties to be put on the train back to Dallas. (I also called Mr. P's babysitter to tell her that Mr. F was handling it in case someone was calling her and cursing her out).
When we lived in San Angelo our number was 1 digit number different from a Realtor and 1 digit number different from a dentist.
One day I get an aggitated call from Mom convinced I had left the internet up at home (had dial up on a laptop). The phone kept ringing and then she would get these tones. I go home. Explaining again that I had my laptop at work. I answer and tell her it is a fax calling us. So I call the Realtor and let them know.
Oh we are so sorry if this is us. We will put a sign by the fax machine and let everyone know that if they are expecting a fax that hasn't come in to call person and have them check the number.
Dentist - We don't get faxes stop bothering us.
I call the phone company and they tell us to dial #9876543210 the next time the fax calls and it will knock it off line. We do - not 2 min later we get a voice call cursing us out and threatening legal action if his client loses the house they want because we can't accept a fax. I coldly told him he had been faxing a private house for HOURS and gave him the Realtor's phone number.
The Dentist office was a pain. We would get almost daily calls from patients. We would try and let the dentist office know that John Smith had left a message one our machine for them only to be told off. We answer the patients, often elderly, would tell us that our number was on the stationary. (The difference was something like a 3 and an

Dad ran into the Dentist at some function - and let him know the problems we were having. He had some of the cards on him - the print was small and the 3 looked a bit like an 8. We stopped having so many problems a little while later.