How to respond/cancel vague date plans

I spoke on the phone with a guy last week and we said we would meetup on a day next week. We haven’t texted or called since our conversation last week, and never solidified a time or place. I assumed he was not interested.

It’s day of the date and he reached out to me for the first time since the phone call last week asking where we should go. At this point I am not interested.

Any advice on how I can respond in a respectful way?