Locked out of game pass account with upcoming payment renewal.

I would check in your Microsoft account to see if there are past due payments there, to make sure the emails are genuine, unless you know for sure that you do owe past due amounts. Then, yes, you'll need to settle the past due amounts and make a payment.
If you had an auto-renewal for Game Pass active and it auto-renewed, but you didn't want it to, you would have needed to cancel it yourself before the next payment was taken out though.

To cancel auto-renewal you need to go too the xbox website then go too payment and billing find Xbox game pass then turn off auto renewal on the game pass

then it should cancel your auto renewal.

That shows a billing issue

You need to contact support

You can't use a prepaid code as a payment option it only adds time so if you owe money for a upcoming renewal (remember billing date is different from renewal date and can be the day before)

Hi and thanks for reaching out. I hope you’re doing well. I'm an Independent Advisor and a Microsoft user like you and I'll be happy to help you.

The Xbox Game Pass subscription is set up to automatically renew each month, and the payment method used for the subscription is based on the available balance in the account at the time of renewal. If you want to prevent the subscription fees from being taken from your children's account balance and instead charge it to the payment card, you can try changing the payment method or making your card as the primary payment method for the subscription by signing in at https://account.microsoft.com/services.

Hello, the gamepass is an autorenweal so you need to have a suitable payment method in place for after the game pass so it can auto renewal after the $1 offer runs out.