Dailybeam

I am in the process of having a custom computers built for my business. Our old computer, were exactly that, old and inefficient. The techs pulled off all of our data from the old computers and assured me of a secure hard data drive destruction on our old hard drives, but I am still nervous. There is personal information on each of those hard drives and I need to know beyond a shadow of a doubt that they are destroyed and nobody could pull any information off of them. Is there anything else I can request of the tech company we are working to assure me that they are in fact destroying the drives?