Frankie Blake, 63, from South Molton, Devon received an £85 parking fine earlier this year when she overstayed her two-hour limit because she was administering life-saving insulin before she set off on her journey.
Frankie said she received the fine from private parking firm Private Eye after parking at Barnstaple Business Park earlier this year.
"I went to see if there was a parking warden around that I could warn before I treated myself but there wasn't," Frankie told This Is North Devon.
"My car was photographed going in and out of the car park."
Naturally, Frankie appealed against the parking fine to both Private Eye and independent appeals body Parking on Private Land Appeals (POPLA), that was created specifically to help motorists contend private parking charge noticies.
Despite providing medical records showing she was below half the DVLA's recommended blood sugar levels, she was told she still had to pay the fine or face court action.
Frankie said: "The appeal decision gave me no details as to why it was rejected.
"I would go as far as to say that they are discriminating against me. They have taken no account of the mitigating circumstances. I would go to court if I have to. I can't see how a judge is going to make me pay."
POPLA refused to comment on the case citing the fact that it was unable to comment on individual cases.
Although relieved by the final decision, Frankie is still frustrated at the lengths she had to go to get the parking fine overturned. She added: "I sent them every single piece of paper which was about half an inch or more of documents.
"I can't understand why they have only decided to drop it now, and I can't understand how POPLA can call themselves an independent body if they don't even look at the circumstances."