Does anyone actually respond to open tickets or is it better to use this forum instead?
I have billing issues, and was trying to add team members, but am running into some trouble. My team has now abandoned the project due to lack of response and moved on to try another platform.
Thank you for your consideration.
Hi, ! Welcome to the Vercel Community.
Our community space is the best place to connect with other community members and customers, as well as have open discussions about everything in the Vercel ecosystem.
Because we'll need to discuss private account information, it's best to open a support case at vercel.com/help for this. Customers on all plan types are welcome to open a new case for any billing issue.
Just describe the problem to the AI chat bot and click the “Create Case” button that appears at the bottom of the chat window. The AI will autofill the form based on the info provided. Then, you can review and adjust any info in the form before submitting it to reach our billing experts.
Please let me know if you have any other questions 
I've done that three times since last Friday. Is there an SLA for paying customers?
We're currently going through a long list of billing cases, and will get to yours as soon as possible.
From the following guide:
Tickets are processed by the order in which they are received. This means that, when you submit your request, you will need to wait for all requests submitted by customers on the same plan as you to be fulfilled before a response is received.
We highly recommend that businesses with production critical workloads or time sensitive deployments put in place a support plan or SLA.