When you see the "pending" state for an interview request, it merely indicates that the request has been sent to the developer, not necessarily that the developer has read the request.
We have an agreement with developers that they are required to respond to you within 48 hours of receiving the request.
If a developer hasn't responded to your interview request within 48 hours, let your Account Manager know which developer you're waiting to hear from. We'll get their Talent Advisor to reach out and ask them to respond.