Problems adding on Stateside International

USA Stateside International

Hi! When I bought a new phone several months ago, the Stateside International feature seems to have gotten deleted. We have had that feature for years and we need it.  I have called T-Mobile about 10 times now and every agent promised me they would add it again to the line, but they did not seem to have succeeded. I cannot add it on myself online, the system is telling me it is not possible at the moment. Has anyone ever experienced that, or can you think of what to do? I simply cannot keep calling T-Mobile every other day….