Blesta provides PayPal with all the information it needs when it's making a payment with the gateway, however sometimes PayPal gives up a fuss and plays up, which is why it's recommended to give PayPal a IPN url.
I've never heard anyone else have a ticket open for a month, did you even try and bump it, ask Paul on here to check up on it? Phone or email them? Or just sit there and hope. The guys at Blesta are human and emails can get lost.
Hello mate, this might help you: https://licensecart.com/billing/plugin/support_manager/knowledgebase/view/279/how-can-i-sell-a-product-without-a-module/11/
If you are trying to add configurable options to products I can try and do a tutorial haha took me a while to get around it myself.