I am very disappointed by vfs global, I paid for my application on the 6th of May using online payment and it was showing that I can book an appointment

I am very disappointed by vfs global, I paid for my application on the 6th of May using online payment and it was showing that I can book an appointment. Upon trying to book I couldn't select a time because it was not showing the times, then I logged out. When I logged in again it was now showing that I can not book an appointment the same as it would show when you haven't paid. I have tried emailing the person I was given but nobody responds