The person who previously responded is correct. There is nothing the Housing Authority can do in this instance. If there was no stipulation in your contract with the Buyer about vacant or non vacant then it may wind up having to go to the court if the tenants were not provided enough time to relocate or if they do not want to relocate.
If you sold the hose then it's not your problem it's the new landlords problem he need to go to the municipal building in the town the house is in and make a report.
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