This should probably be a linked multiple choice market instead of unlinked. All the options should sum to 100%. I think you can do this by selecting "resolves to one answer" when creating the market.

I might even go so far as suggesting you NA this market and make a new one.

@Fion I don't know how to!

@HarryHayfield go to "create a question", select multiple choice, then where it says "how many answers will be chosen" select "one".

If you also want to cancel this market, there should be a little button that says "resolve" and when you select it it should ask how you want to resolve it and "NA" or "cancel" should be an option.