I wasn't entirely sure which forum to put this in. I don't think it's technical enough to go in technical support, so I'm posting it here.
How does one renew them when operating entirely off of time cards? I never *technically* subscribed...(at least not in the sense of the definition of the word)...
And yes, I did actually Google it. Google seems to be borked these days.
If you are only using time cards, you won't be able to buy or renew retainers with them. You'll have to buy them separately, I guess you can think of them like the optional items.
The same way you purchased them the first time? Retainers were never tied to your game time, they're a separate service. You get 2 for free in-game but if you have more you had to have purchased them at least once before.
You may be able to pay for them using Crysta. Not sure about that though. Also not sure if there's any way to get "Crysta cards". Might be worth checking these avenues out. If not, as Billy said, same way you got them the first time.