The date of an invoice to be issued each month shall be the last day of the month. also note that such invoice will be mailed on or before the fifth business day of the following month. If a tracking tag is ineffective due to a reason imputable to the advertiser side and the tracking tag is ineffective due to a reason imputable to the advertiser side and the tracking has malfunctioned, the results-based fee amount shall be calculated based on, among other things, the number of clicks during the relevant period, which shall be borne by the advertiser.