Is it still getting up to temperature?

If so then you need to unload it but pull it as it is unloading, do not pull hard enough to snap the filament or you will have to pull it apart again to clear it out. Once unloaded then cut off 3 inches and reload it again. The reason it may not unload is that the jam has caused the filament to be stripped so the pull push wheel can't pull it hard enough.

What filament are you using, is it known to be good filament?