CBSubs and Quickpay - two users have paid for two years subscription ??

Ahhh.. and another comment from Quickpay support:

"If you want only to use a callback, when eg. a capture is completed, then you unfortunally would have to deactivate autocapture. We are sending callbacks for all operations on a payment. So then you would have to not use callback on auth, and then make the capture yourself, after you through the API can se that "accepted:true", send capture request with callback.
But - we recommend not using callback at all or only use it as a failsafe."

I do not agree with their implementation based off my experience with payment providers for the past 10+ years. My recommendation is to just not use QuickPay, but regardless the workaround is implemented into CBSubs and your install is already patched with it. If you continue to have issues we'll review other possible solutions.