Hi guys! I know there is a little bit of confusion so I wanted to help clear it up =p Thanks everyone for helping!

To answer the Original Poster's question, you definitely can buy both "Monthly Card" and "Platinum Monthly Card". You can re-activate these at anytime so long as they were inactive/expired first.

The "Platinum Monthly Card" does have a requirement which I posted the reference below. The requirement is that you must have either recharged 300 ingots or more on the day you want to buy the "Platinum Monthly Card" or have an active "Jonin Medal".

Hope this helps!

Reference: