Couple weeks ago I bought myself a Monteverde Artista Crystal in the lime green color. It has a medium nib and takes standard refills. Here is the issues….. It doesn’t write, no ink flow. I have tried both the Monteverde black ink cartridges as well as the J. Herbin Perle Noire black cartridges and same issues. If I run it under water for a couple seconds it works but only for that session, if I leave it for a couple hours it no longer works again. I tried blowing gently into where the cartridge connects in case it was an air bubble and again it worked for a bit then nothing. Can anyone else think of something I should be trying or should I just return the pen?