Can a landlord cut off your utilities that are furnished with your home? Please advise me on what to do if this happens.

When I moved into my home I paid $600 to cover an entire month's worth of rent. The landlord accepts rent on a weekly or monthly basis. When rent became due last week , I paid the rent on Friday and told them I would be paying weekly from now on. They agreed to this and accepted the rent, I kept my receipt. Tonight, one of the landlords representatives came to my home and stated we owed rent. I informed him that we paid on Friday. He said that we still owed $500. I told him that the girl who took our rent in the office stated she would change it from monthly to weekly. He told me that we must come to the office before 9:00 am or they would cut our electricity off. I went back and reviewed the lease and it showed that the landlord would furnish the electricity as long as rent was paid.