GTS and BAS

We have old data we have not yet processed so there is a list of GST pmts awaiting completion. They are for qtrly GST periods Jul16-Sep16, Oct16-Dec16, etc onwards so I need a workaround please so they clear off and the bank account is duly updated. Any help would be great, Thank you.

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I have created a journal entry as suggested that has zeroed out the BAS suspense balance but the payment isn't reflected in the GST centre. Does anyone have advice on what I might be missing?

The example being we are selling tickets (which include GST) for a future event.  From my reading the double entries are 1) Credit Bank Account, 2) Debit Unearned Revenue.  When the event is happend I can then credit Unearned Revenue and Debit Earned Revenue. The question I have is when would GST be liable given I collect GST upfront but only recognise the revenue later on.   Also keeping in mind that there is the ability to cancel tickets (albeit with the loss of a % of the ticket).