If you suspect having two accounts, you can try checking it out yourself. One possibility is that the web account uses different ID than your phone app. On the phone app, go to Menu » Settings » App Diagnostics and note the Displayname code. Then open the web interface, click your avatar in the upper right corner, and select the option View Profile. Now compare the ending code in the address line of the browser, with the code from the phone app. If they are not identical, you have two differrent accounts, and need to use the same one on both sides. You can log out of the web account, and log in back using the identification from the phone app.
Another possibility is to follow the instructions from this support document