Mobile Shorten Short Links being hacked?

I recently used bit.ly and goo.gl shorteners in an SMS campaign I was running. One of my subscribers e-mailed me and said that the link, which I set up with these providers, was taking them to FOURSQUARE!? And not my intended destination? When I email the link to myself and open it using my PC in a web browser, everything is fine. When I text myself the link, sure enough, it takes me to the Foursquare home page. Hmmmm.... Can anyone shed any light as to why this is happening? Is there a safe shortening service to use? I can link subscribers directly, but then the subscriber will receive 2 sms messages because my character count is to long. Looking for help.... Obi-Wan are you out there?