Same thing just occurred to me after an expired rental period. I ended up with a starter Hybrid and no Irons. I figured it out albeit a bit of a bizarre way of removing the Hybrid and equipping the 3rd wedge.
In the desktop version: On the "Edit Equipment" page, I found the Irons in the 64*W as an option. I replaced the 64*W with the Iron set, then clicked on Hybrid on the left side of the page and then click Wedge at the top of the page, Choose 64* W to replace the Hybrid.
Hope this helps.... henry