Which way to pay my first payment for BCBS Marketplace plan?

I'm sitting on the "You're almost done" screen of healthcare.gov for my Blue Cross Blue Shield of Texas medical plan. There's a statement that reads "To avoid cancellation, you must pay your first month's premium by the estimated effective date of 10/01/2024. (Contact plan if you’re in a Special Enrollment Period.)" But there's also a link that takes me to a web page (https://apply.bcbstx.com/retailshoppingcart/TX/exchange\_referred) where it offers to let me pay. But I'm still worried about that "Special Enrollment Period" caveat so I don't try to pay using that page yet.

Just in case, I contacted the phone number listed (888-697-0683). The person I spoke with told me I had to wait 1-2 weeks for the marketplace to send the paperwork to BCBS in order for me to pay. She showed me a separate webpage (paymentportal.bcbstx.com…) that gives an error message "The information you provided does not match any of our records. Please review and try again." The error message is because they haven't received my files yet. However, I'm aware that the people on the phone don't always have all the answers or the full picture. They may not know about the link on the marketplace. Plus, if I have to wait a week then I'll be cutting it super close and it'll be 9/30 or 10/01 and the marketplace is threatening to cancel my insurance if I don't pay in time. I've been told by other people on the phone that I'm supposed to be able to pay right away, that there was no "processing" or "communication" time.

So I'm hoping someone has navigated this before. Do I just go ahead and pay using the link on the marketplace that takes me to the apply.bcbstx.com website, or do I have to wait a week for paymentportal.bcbstx.com and pray i make it in time? Thank you for any help you can offer.