Leakage of urine from a closed cat toilet

I have had 2 cats for several years and I always used an open litter box for their needs. I bought this one because I liked its design and to limit the sand that inevitably escaped from the open box. I liked it so much that I bought two.
It is really a well-made and very beautiful product, with a practical door and an opening from the top for the cat to choose how to enter and exit. Also useful and practical is the "sieve" at the top to catch any sand grains that stuck to their paws.
The sand is easy to clean as there is a drawer that you pull out for easy access. Theoretically. Because here is where the positives end and the negatives begin. Or rather the negative, as I found one but very important: both the sand and the urine leak from the toilet and come out at the bottom :(
Unfortunately, the connection between the top and bottom of the toilet does not close as it should and does not create waterproof walls, so in a strange way, the cat's urine leaks, wets the bottom of the toilet, and comes out, with all the unpleasant consequences that this entails. And all this in a closed cat toilet.
I noticed this in both toilets I bought, so it is not a question of a defective product but of a construction flaw. So it goes back to the warehouse and we are looking for a new toilet that can retain both the sand and the urine of our beloved pets inside.