When my sister and I met with our landlord for the first time, he told us that we would be given a 5 day grace period. Now he is saying we were given a 3 day grace period only in case of emergency. He has already failed us on our lease, so when we passed one day on his so called "three day" grace period, he threatened late fees. However, several people have told me that homeowners, leasing a home, are required by VA law to give a five-day grace period, and cannot legally charge late fees, on the first offense, unless the rent is paid over ten days late. Is this true?

I can't find anything showing that VA requires a grace period at all. Few states do.

In fact, Code section 55-248.7(C) states
C. Rent shall be payable without demand or notice at the time and place agreed upon by the parties. Unless otherwise agreed, rent is payable at the place designated by the landlord and periodic rent is payable at the beginning of any term of one month or less and otherwise in equal installments at the beginning of each month.