Was I just ripped off? Catalytic converter or O2 sensor?

YOU HAVE A 1996 THIS CAR IS 15 YEARS OLD PUTTING A NEW CAT ON THERE WAS MONEY WELL SPENT ALSO NOW THERE'S A NEW CODE SO HE FIXED P0I40 NOW ADDRESS THE NEW CODE UNFORTUNATELY THIS IS WHAT YOU HAVE TO DO TO RESOLVE THESES TYPE OF ISSUES.