Consumables for your Citizen printers can be purchased from a wide range of locations, generally from internet-based online supplies companies.

Using a search engine such as Google and entering "Citizen Printiva Cartridges" will generally give you a broad range of suppliers.

If your regular supplier cannot provide your requirements for Printiva ribbon cartridges we can recommend SwiftClik Limited.
They are based in the UK but will happily ship worldwide by prior agreement of shipping charges and accept credit card payments online.