Charging and connection problems

I have a IRobot Roomba 891. One of my dogs pooped in the house and the IRobot. “cleaned” it up. Actually, poop was smeared everywhere. I tried to clean the IRobot as best I could. Now it is not charging when it goes back to the base. I am able to fool with a bit and finally get it to charge but then it will not self start. It will sometimes, but not always, manually start. How do I get it repaired?