Montecristo Pen Set - Help

[Mr.Maduro]

A while back I got the Montecristo Sampler pictured below with the free pen. Well the pen just ran out of ink and I'm trying to find a refill for it, but the cartridge is absolutely blank, no numbers, info, nothing. I really loved the way this pen wrote, the feel of it, plus the built in 9mm punch and would love to get a few more refills for it. Any ideas?

Thanks in advance.