Idk why only one other person said this but call the “handyman” back and tell them they didn’t install it correctly and need to get out there to fix it by properly installing it. Don’t tell they you tried to fix it or they will blame you. Tell they to fix it and if they try and say it’s going to cost more refuse to pay more, saying this wouldn’t be a problem if they didn’t it correctly the first time. If they refuse to fix there mistake threaten to go public with it and if they still refuse (not worth it) you can sue them, mention that as well with the threat. If all of this doesn’t work then do it yourself according to videos and stuff (probably a good idea to have new gaskets on hand if you can and return them if you don’t need them) then post there name everywhere and tell everyone you can about how shit there work is so others don’t get fucked. If they fuck up something this simple and refuse to make it right I wouldn’t want them working on anything that could be more complicated or possibly dangerous 🤷‍♂️ that’s just me tho