Nexon update
Hrm...I don't think anyone cares anymore and the cash shop limit was taken care of months ago, but it's only fair to Nexon to post their (finally competent) response:

Greetings,
We are sorry you have been having issues with your questions being answered properly. You should have been directed to the official Nexon website, www.nexon.net, instead of the Maplestory one. Unfortunately this site is not completely updated and would not contain the answer to your questions. As for the Premium Service, it is indeed stackable so multiple purchases will increase the duration of the package itself. As for the paypal limit issue, that is not something we are at liberty to discuss but is not something we are able to adjust on an individual basis. We will take your suggestion to increase the limit and forward it to the correct department for consideration, as the need for it is evaluated periodically. We do apologize if this is inconvenient for you. In the meantime please feel free to visit the official Mabinogi website, mabinogi.nexon.net, for any future announcements or game related information as it will be continuously updated.

Thank you,
GM /blank/

Sorry for not updating sooner!