[tsac]

You can try deleting the contact and then resend her an invite. You said her invite is in your sent list. if thats correct then she did not send it you did. Try pulling the battery to reload the OS on the phone. Try having someone else send an invite to see what happens. Reverse and do the same with them to see if they get it.

If all that works but you still cannot get a response from her, you might go with the blocked issue.