Can not Upgrade plan and support have not responded in 3+ weeks

I am sorry to hear this.

May I ask if you’ve followed the instructions here?:

Furthermore, questions about billing will need to be resolved by the Customer Support team and cannot be resolved on the Community. You can open a Billing ticket here, https://dash.cloudflare.com/?to=/:account/support

Kindly, may I ask you to share your ticket number if you’ve got it? Thank you in advance.