We apologize that you are having this issue.
First, go to etherscan and enter your SWT wallet public address into the search bar. You will see your SWT and ether balances so you can relax.
Resolution: Clear your browser cache or use incognito browsing
For instructions on how to clear your browser cache here are some helpful links:
You can also try visiting swarm.city from a different browser if you don't want to clear the broswer cache.