How to get rid of Spanish bluebells

I have been unsuccessful with getting of rid of these bluebells and they are now a pretty solid mass under a fig tree. They have also spread to other areas. I have tried digging them up but one tiny overlooked bulb seems to multiply very quickly. I posted many years ago about them but they seem indestructible. Any ideas very gratefully received.
Margaret

 

Covering them with a deep mulch or landscape fabric should work. I have the same problem with crocuses and Grape Hyacinths, as well as bluebells; but my plan is to dig them out as soon as I see any green leaves poking out of the ground. I expect it to take at least a couple of years, but it should make a good retirement project.