Hi,
In order to know why the paypal response is invalid, we have to know more about the notification message.
Please check that your paypal callback url (in your paypal account) is right pointing to the "paypal" plugin and not the "paypaladaptive" one.
You might see more details in the order history or in the payment log.
About the commission, I do not understand your problem. You said that the created order have the amount that the vendor should receive as commission so where is the problem ?
Regards,
Jerome - Obsidev.com
HikaMarket & HikaSerial developer / HikaShop core dev team.
Also helping the HikaShop support team when having some time or couldn't sleep.
By the way, do not send me private message, use the "contact us" form instead.