Avaya Firmware Nightmare 4850

I’ve recently purchased a used Avanya Ethernet Routing Switch 4850GTS-PWR+ to upgrade a current network setup. I was looking to upgrade the firmware to the latest version however the firmware must be upgraded in steps. There is no access to the Avaya website to download any images. As you may know extreme networks bought out Avaya. Extreme networks provide updates to the said switch however the firmware offered by them starts with version 5.9 and above. The problem is to get to 5.9 you have to be running 5.65 or 5.7. The switch I purchased comes with version 5.63. The old Avaya site said you should have downloaded all the old copies and kept them safe but its now too late for me. Extreme Networks won’t allow me access to 5.65 or 5.7. What do I do or has anyone updated there's higher from 5.63

I’m currently running HW:12 FW:5.6.0.18 SW:v5.6.3.024 BN:24

And to get to 5.9 would need  software image 5.6.5 or 5.7 and diagnostic image 5.8.0.01 or 5.8.0.03. Been looking for a solution for days but may have to look at another switch.