Help please

I recently had my catalytic converter stolen. I purchased the kit from Rock Auto because the dealer price was extremely high. We installed it. It ran good, but noticed the check engine light would pop up every 4-5 days. Then the truck starting running as if it was missing (bad spark plug) and I noticed it was wasting alot of gas (4 cylinder). And sometimes it struggled to pick up speed ad I entered the highway. Now the check light comes on every other day, still missing, and hesitating. But now it sounds like I installed a fast and the furious muffler.. lol.. honestly, it always sounded like a lawn mower considering its a 4 cylinder.. but now it's louder than it originally sounded when I purchased it. Long story short, I ordered the wrong kit, which would explain the problems. My question is, can I just take off the two converters, and run a straight pipe? Would that fix the problems? And if I do that, what do I do bout the two sensors that will no longer be connected? Or, can I buy the adapters for the sensors and leave tje converters I already have? Will the adapters make it run better? Or eliminate the problems all together? Thank you in advanced.