We are very sorry that you are having a problem with the backplate. The screws should have indeed been taped to the PCI backplate. To get you through the installation you can use the screws in the spare parts kit. They are the ones that look like this:
We do have an email its CS@caselabs.net and it can be found in the "contact us" page on the website
People make mistakes from time to time, but we will take care of the problem. Can you please PM me your order number?