Hello Ike Mekwunye,
Thanks for your question.
To cancel a free trial, turn off recurring billing. If you don't turn off recurring billing, after your one month free trial ends, you're charged the applicable subscription fee. If your trial subscription doesn't have a payment method associated with it, you can just let it expire at the end of the trial period, and you won't be charged.
To request a refund you need to cancel it first and follow the steps similarly documented here: https://support.microsoft.com/en-us/account-billing/how-to-get-a-refund-on-a-microsoft-subscription-67dca30b-b323-44d5-acc2-e02f9902c472
Regards,
You can mark it 'Accept Answer' if this helped.