Visa date is approved by Counselor. The nature of VISA is same as HKID. Your maid should have a valid document otherwise she will ILLEGAL to stay HK and can't work. So, she needs to pay visa fee by herself, not employer - you.
Contract is signed by you and maid. Your maid should leave Hong Kong upon completing the contract.
Please read the contract again now and make sure the lastest date i.e. period from xxxxxxxx to xxxxxxxx (latest date).