Input tax credit

Hi sir, My name is Athar Khan i am branch accountant in Dehradun i want to know that i punch purchase invoice for the M/O July,15 in March,16 & take ITC at the time of VAT payment. now i am filling VAT return for 4th Quarter but system not accept purchase bill July,15 in 4th quarter return. please sir tell me what i should do in this case