Calling Dr. Prick

There's a doctor who lives in the building where my accounting firm is located. I always used to see him and say hi, and he would exchange the courtesy. So one year, maybe 5-6 years ago, it was April 14th and he came running into the office. He was in a panic because he waited so long and hadn't filed his tax return. So we agreed to do the job at our usual rate (regardless of when you come to our door we'll do the work for a fee determined by the necessary amount of work). We called him to let him know it was ready and he picked it up. Immediately his face crunched in when he saw our fee. It wasn't exhorbitant. In fact it was less than we would normally charge since he was new. It seems he felt gauged and never came back. To this day he refuses to even say hello or exchange any sort of pleasantry. He has even been such a prick that he's fucked with the elevator, sending it to all the floors when he knows I'm waiting for it, just to be a petty, rude bastard. What a total bitch-ass.