Do not continue the lease with them anymore.

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.