If they continue to get you more problems after all these fixed, do not renew the lease anymore, get them out from the house. I think they are not 省油的灯. You need to stop the trouble instead of letting them last forever and hurting yourself.. A lot of time, High education or High job do not mean anything when the personal character is low. A lot of highly educated people act low and sometimes even worse than the low educated people, never let their education and job titles fool you.