Hello!
My check engine light came on and I had the catalytic converter replaced and the O2 sensors as well. I am not sure if they replaced 3 or 2 but will verify. The light still comes on and the code is still the same, catalytic converter. What can I do?

Well, I can speak for Toyota's, that I've seen many aftermarkets installed and the code comes back. The fix was an oem converter.
I've heard this on many other makes too.

I assume the code that's being stored is a P0420? If so, there has been some information released by the Wisconsin DOT that states that a P0420 code isn't always a faulty converter. They list possible causes as:
• Damaged pre-cat exhaust manifold or pipe
• A faulty downstream oxygen sensor
• High fuel pressure
• A faulty coolant temp sensor
• A cylinder misfire

I would explore those options as well before resigning to another converter. Good luck!