Deathadder Elite Side Button Don't Work

One of the side button of my mouse stop working and I don't know what to do. I already contacted the support but nothing work. I try to: plug the mouse in a different computer that doesn’t have Razer Synapse installed, reinstall the mouse driver and synapse, clean the mouse. I can't do a RMA because I lost my receipt so if anyone have an idea to how to fix this pease tell me. Here is the video of my issue: (In the video I bind the first side button with the number 1 and the second side button with the number 2 and as you can see the second button is not working).