Get the igloo 48qt cooler someone suggested here from Walmart. It fits perfectly in the trunk cavity and will prevent things like this the next time.
My wife and I just keep a couple insulated reusable grocery bags in our cars (my model 3, her model Y). Anything (and I do mean anything) that could leak, melt, drip, etc goes in one of those bags in the trunk, when we go shopping.
This includes things like wine, spirits, ice cream, meat (in its packages) etc. The only thing that doesnt go in those insulated bags is stuff like fast food / take out that we are picking up, and that goes in the frunk unless one of us is actively holding the bag and eating (which isnt often actually).
The insulated bags we have are from Costco, and we have had them a few years now. I think they cost like $9.99 each when we bought them, and we have 4 total. My wife also has an additional one beside the 2 costco ones in her model Y from trader joes, but same deal.