I cannot believe that this was TiGold. You may have had a kit that was wrongly labeled. I have buffed assembled pens, both TiGold and Platinum, and never have removed the plating. From what company did you buy the kit?? Berea's TiGold is excellent and should hold up very well. I have no experience with CSUSA TiGold, but with their Rhodium and this held up well when I buffed it. Titanium Nitride coatings, that is what we call TiGold, is a very, very durable plating and is widely used in forging tooling, as well as other tooling for cold forming and cutting tools are also often coated with it (you may have seen these gold colored drill bits).
Update: I just went down in my basement and did a test. I buffed an old TiGold flattop pen that I carry and use for at least 5 or 6 years.
I loaded my wheel freshly with white diamond and buffed the clip of the (old, used) pen for exactly one minute at 1200 rpm. There was no change in the looks, it looked the same as before. So, this for me is an indication that you did not have a TiGold kit!!