It seems you may have purchased a subscription for Microsoft 365 Personal, which typically involves a recurring billing cycle. The initial charge you noticed was likely for the first month of your subscription, and the upcoming charge is for the next billing cycle, which is usually set to occur monthly unless you change the billing frequency or cancel the subscription.
If you believed you were signing up for a free trial, you might need to check whether you turned off recurring billing. If you do not turn off recurring billing, you will be charged at the end of the trial period. To cancel your subscription and potentially receive a refund, you can follow the cancellation process outlined in Microsoft’s support documentation.
Please note that the ability to receive a refund may depend on the timing of your cancellation and the specific billing account type you have.
For further assistance, you can contact Microsoft support directly for help with your subscription and refund request.