Where is the Pay-As-You-Go Calling Plan for GCC Tenant License

Currently we are using Direct Routing for calling and want to transition to a PAYG calling plan for GCC license.  Unfortunately, direct purchase through Microsoft 365 Admin Center "Microsoft Online Subscription Agreement" (MOSA) billing account is not available; and the license does not appear on our reseller "Microsoft Customer Agreement" (MCA) billing account price list.  Microsoft’s Modern Work FAQ – Microsoft Teams (last updated July 29, 2024), item 103 states pay-as-you-go calling plan is available for GCC. Has anyone successfully purchased a PAYG calling plan for GCC license since the implementation of the new Microsoft billing experience?