Afraid not. Once your payment has gone through, you are locked in for that issue and it can’t be cancelled. You can cancel your subscription now and you won’t be charged for any subsequent issues until you re-subscribe. You will however, still receive the last issue you have been charged for.
Payments are taken on the 2nd of the month, you will need to cancel after the 2nd and before the 1st of the next month to ensure you will not be charged for the following issue.