I work at Nutrisport in Iowa, we had one last shipment in of Mass Tabs last month and they skyrocketed out as soon as they hit the shelves. The reason they were discontinued, to what we understand, is that they had a steroid derivative in them 'stenbolone' and a couple other negotiable ingredients that fda would not approve of.
If you call looking for them they will offer 'Super Mass Tabs' which we all know will not be anywhere near as good. People have been buying Bulk Tabs from us now, same company, apparently giving good results - don't take my word for it though.