Pro Sites 3.5 - can't upgrade with stripe


After installing Pro Sites it stopped working with my template.

I can't upgrade a site to the Pro level with a stripe gateway. I am using a Stripe in a test mode.

I applied a patch from the forum and it downgrade my version to

After the checkout I get the message that subscription ends today. So when I try to upgrade on 7th July 2015 after checkout it shows the subscription ends 7th July 2015. So it doesn't upgrade. Can't see any upgrade changes in a dashboard and network dashboard as well.
In Stripe pane;l there's a new customer created but with no card details or payment.

Somehow I managed to successfully walk through the whole checkout process on the default template (Twenty Fifteen) with all plugins deactivated. After switching back to my template (all plugins deactivated) I can't upgrade any site.

Webhooks and API keys are correctly configured.

Could you please provide the solution as the plugin was working OK with my template and now it stopped.