Payments made to Parkmobile will not necessarily leave your account on the same date that you pay to park. Any financial transaction quite often takes up to five working days for your card issuer to debit the funds from your account despite it having been authorised on that particular date.
In near all cases what happens is similar to when you take a trip to the grocery store. You may buy groceries on Saturday, but then not see the charge posted to your account until Monday or even Tuesday. Before you query your statement with us, we would recommend that you pair your card statement with the Tax Receipts that appear against your parking account and if they are equal in number, ignoring the dates, the chances are that there has been a delay with the funds leaving your account.