Why is my toilet backing up and bubbling after replacing an ejector pump?
You have a clog downstream of the pump most likely.  It might have even died because of this (overheated?).

You will need a drain auger/snake in order to clear this.  If it's close to your access point you might be able to use a small handheld one, but most likely you'll need an electric drum snake:



You can rent these from most home improvement stores.