I recently replaced the old bedding in my bin with store-bought compost. Every single worm I had died within a day. Do you perhaps know what the reason for this is?
I am sorry to hear that you lost all your worms. Did you find any remains of worms on the surface of your worm bedding? I suspect that the compost you bought might have been to high in pH and your worms had no way to escape the acidic environment.
I am not sure why you replaced the bedding we supplied but I suggest in future to contact your nursery and ask them to test any compost that you want to use as bedding material for your worm farm. A material that is usually safe to use if you want to start up a worm farm is torn up wet newspaper strips.
For more information about starting up a worm farm go to the site map of my website www.worm-composting-help.com where you will find many articles that will assist you to successfully recycle food waste and other organic materials with the help of earthworms.
Stephan Kloppert Author of "How to start a profitable worm business on a shoestring budget" Editor www.worm-composting-help.com