where to buy Max Carta replacement pen?

Hi everyone,

I'm really kind of desperate right now...

I bought an Onyx Boox Max Carta in 2017, but lost the input pen. The ereader doesn't have touch input, so right now I cannot use it at all.

I tried to buy pen from two different stores, one on Aliexpress and the other in China, but even though they both advertised that it is for Boox Max Carta, and the pens they delivered did work on my Boox Max Lumi as pen input, they do NOT work on Boox Max Carta. I don't know whether Max Carta has a special EM input layer or why.

I would love to buy a replacement pen, but  Ihave been burned twice, receiving non-functional model. Does anyone have pen for Max Carta, new or used, for sale? If not, what kind of pen should I buy and where I can get it? I don't want my Max Carta to fail because of not having a pen, since it has no touch input!

Any advise or hints would be most appreciated! Thanks in advance!