The new in-game shop is not compatible with subscriptions. You can add to cart only one-time purchases, so if you have any VIPs that you provide as one time and subscription at the same time, you can't use the in game shop at all.

This is what comes up with debug enabled:
[TebexPlugin] [Tebex HTTP] -> POST https://headless.tebex.io/api/baskets/dsxj4q-e68f29bbb4dc18b9673c1de15fc930a2aefc4a37/packages
headers: Content-Type=application/json, Accept=application/json
body: {
"package_id": 3627732,
"quantity": 1
}
[TebexPlugin] [Tebex HTTP] <- POST https://headless.tebex.io/api/baskets/dsxj4q-e68f29bbb4dc18b9673c1de15fc930a2aefc4a37/packages -> 400 (357ms)
body: {"status":400,"type":"about:blank","title":"Please indicate in the request if the package type is single or subscription","detail":"","error_code":"","field_details":[],"meta":[]}

The description of the package itself appears in one long text with no paragraphs like it should be in the shop so it's hard to read and pull out what is impotant.

Last but not least... with adding such features like the in-game shop, please, add an expiration date somewhere. In the shop itself, add a command... whatever can show when their package ends so I don't have to look it up for them every single time. It would be so helpful to many of us!