Column not found in dataset even though it exists in the CSV file?

I've been trying to process some data from a csv file which contains a number of columns, a 'Date' column among them which keeps producing an error. I know it certainly exists in the CSV file, but I keep getting the error message:

'ValueError: Column 'Date' not found in the dataset.'

Found a suggestion online to fix the date format in the CSV file to 'YYYY-MM-DD', but after I try to save the CSV, it keeps resetting back to the default DD-MM-YYYY format. I'm out of options to try, please, help.