You, as the user, can set the monthly spending limit, while the postpaid billing limit can only be set by the MSG91. If you have exhausted the emails and validations allotted according to your subscribed plan and wish to send more emails or validate additional email IDs, MSG91 will deduct the excess usage amount from your wallet when you reach 90% of your postpaid billing limit. After this deduction, your postpaid billing limit will reset to the default. If your consumption continues and reaches 90% of your postpaid billing limit again, another deduction will occur from your wallet. In this situation, the total maximum deduction aligns with the monthly spending limit you've set.