I got the Mt Dew Zero Sugar ($1.25) and Pepsi Zero Sugar ($.25 on 2). Yes, that's a quarter for 2. I might get the Mt Dew, but not the Pepsi.
Ibotta lets you submit a receipt up to 7 days after purchase. If you have already submitted the receipt, you have 24 hours for Walmart receipts to submit it again. I would try it, but I can't guarantee anything.
I'm assuming you aren't linked.
If you are linked, this won't work. You must add offers first. You also can't resubmit receipts for linked accounts. You have to open a ticket.
Assuming you are unlinked, it is as mmoore01 says..
You really should add offers first for your own good. Offers sometimes expire early and if you do not have the offer added, you may not notice if this is the case.