Colombian SIM Card Registration

So I bought a new SIM card when I first got to Medellin, and it turned out to be impossible to "legalizar" on the Mi Claro app because it was already in someone else's name.  So when I got to the small town four hours from Medellin (where I currently live), I decided to buy another SIM card at an "official" (ish) Claro outlet.  They assured me that this SIM card would definitely be in my name-but it would take up to a week to show in the system.

However, when I called Claro, they said that I have not successfully "legalizado" this SIM either, and I am unable to do it on the Mi Claro App either.  So after going in a loop between an app that doesn't work and customer service people who don't understand my problem, I have been told that I will need to visit the "real big official" Claro office in Medellin to sort this out.

This is the first time I have actually been living in Colombia for more than a few months at a time, so I'm a little worried.  Why can't I "legalizar" any of my SIM cards with my cedula?  Can they really magically fix this problem at a "real" Claro office in the big city?  And is it true that my phone will get blocked if I don't do this in a few months' time?