I have a problem with unearned revenue on 31/12/2016, its debit balance with 191626.46

i understod from previous problems with another people about taht account (Unearned Revenue) this account uses against advanced customer payment for services or good or payment for future services to be performed or goods to be delivered

So, i checked the system and found some payment received and payment made with not against invoices, i Fix it and make it related to the bills and invoices that belong to them, after that i checked the account on on 31/12/2016, its debit balance with 191626.46

althougt there is no any amount not relaited to invoices or bills on 2016, but i checked the same accout today 26/08/2017 and i found it credit with 2250 and its correct because there is advanced payment by some customer with the same amount,

why the balance is not correct on 31/12/2016 but it is correct today on 26/08/2016.