Well, no, you haven't - you've simply asserted it to be so. An assertion which, as I point out, is demonstrably false. But don't take my word for it - you should go look up the mechanics of radioactive decay, to confirm what I'm telling you. And then you'll see for yourself that not all things have a cause.
You asserted, "No. Radioactive decay is spontaneous and uncaused ..." Perhaps you are confusing a reductionist perspective regarding symmetry breaking with a concept of emergent phenomena ... the Pauli exclusion principle may be applied to explain decay even though it is not possible to show the causality in action of decay. Tortoise is fond of pointing out (wisely) something to the effect of random is not to be confused with 'uncaused'. That you cannot define the specific cause for decay on the scale of a single atom should not be misinterpreted to signify no causality. With the development of the concept of emergence, we find that indeed all events in our universe of spacetime and all its permutations have a cause, though some causes are unknowable in current research. It is simple enough to prove to yourself: if an event happens in this universe then it is somehow involved with entropy and thus exists under 'causality' not beyond causality.
LOL!
Sauron (The cause merely hasn't been discovered, yet. You're a believer in MAGIC, are you?)