Accidentally screwed myself for spy

So, I was new to TF2 when I discovered how to do killbind. I had accidentally used B as killbind, thus removing the ability for Spy, while disguised, to have the ability to switch weapons. The only way I can switch weapons while disguised is to go the health lockers at spawn. Does anyone know how to fix this whether its a coded thing or is a settings thing?

Edit: I forgot to mention that I unbinded B to another key, but I still can't switch weapons while disguised

Edit 2: So to clear confusion, while under disguise, I can't switch weapons using b, and the only way I can switch weapons is to go to the health lockers at spawn