In practice, tell them you will consider the EULA non binding, and would still like your money back.

If they are still dicks about it, figure out what the authors of the EULA were most afraid of, and do that.

Home run fantasy land: Wait until they sue some other user based on a clause in the EULA, then testify in court, causing them to lose that case, and also invalidate the EULA for all their existing customers.