Regretting the pay up front (Patreon)

Guys.. if you want to change your pledges to higher pledge, please do it next month when you get charged the initial charge first. You guys getting charged again this month for the remaining balance when I've sent out the rewards is making me guilty as hell and losing track of who should be given what D: please I want to keep everyone happy and I don't wanna make mistakes in the long run.