It may just be a story, but it's from my mother so I trust her.
This takes place before I was born, which is a very important fact.
Now my mother's old doctor (who she left for a number of reasons) told her, in no uncertain terms, that she could never get pregnant. Well, okay, so he was wrong. Do you know what he told her once she was pregnant? Her white blood cells would kill the fetus. Yeah, clearly that happened (not!).
tldr; Doctor tells my mother it is not possible for her to have children.
Another suck from the same doctor, and also my mother.
This one is sort of gross.
My mother had some... very "feminine" problems with her... girly part. (I'm trying to keep this safe-for-work here!) Given her family history (some four sisters, mother and grandmother who all had colitis before her) she was pretty sure she had it. She just wanted a test to prove it. He refused, said it was too rare, told her she didn't have it and gave her something for pain.
For many years she took steroids, carbon pills and many other things in an ever-chaining cocktail of medications. She was pale and tired and miserable all the time (she still is, but she's more of an angry-miserable as opposed to her depressed-miserable). Eventually she saw a doctor who (guess what!?) told her she might have a sort-of rare disease called...colitis! In her version she said something akin to "Yes, doctor, I know" (which isn't unlike her). So, she gets part of her small intestine removed, and rebuilt for her large intestine.
She now has trouble eating many fruits and vegetables, and her stool smells something awful, but she's generally happier (well, less unhappy I should say). And she's not on so many medications you can measure he life by what exact combination of pills she's taking.
tldr; Doctor refuses to give test for ailment because it is too uncommon.
I hope this counts as 'Bad Service'. I mean, for the first one, clearly he was wrong. For the second, why not just test someone if they ask for it?