How are you sending data to PI? Are you sending using idocs or proxies? If idocs then go to srm system and check in we02 transaction whether the idoc is created or not. If you are sending via proxy then in your srm system go to sxmb_moni and see any message is created or not? First check in source system whether the message is created for the transaction or not. If yes then you might be missing connections between srm and pi.
I think you did face the Issue " apearing of UWL screen instead of Shopping cart in Powl"
Even i am also facing the similar issue.I have just copied the shopping cart number and placed at search bar (being displyed at right top most side) and clicked on the button " Check out". then instead of shopping cart , UWL screen is getting appeared.
It would be a great help , if you can share the information how it got resolved for you.