I used to have stock of the type of the cancelled stock certificate you mentioned. It was very difficult to exchange it for valid ones and it took me 3 months or so before I managed to get it converted. For a while it looked like all my money in this stock might have been lost. Apparently there is a 5 year limitation or so, and if you are within the 5 years after the name change, there are channels to get your money reimbursed. I think we are now close the the 5 year name change or have just past it, and would not touch it.