Stuff in my tank

Hey guys a couple of nights ago I found out someone put something into my gas tank. I don't think it was sugar but anyways I changed the fuel filter and put some fuel injector cleaner. Oh and I also put super unleaded fuel. Anyways it helped a little but my car still hesitates when I am in low rpm's and i floor it. Also recently it stopped starting.... I have to push start it to get it to run. So I had 2 questions. Is there anything else I could do to try and make it run better at low rpm's and would putting higher octane fuel cause it to not start?

sound slike they mave clogged your fuel pump. you may want to checkinto that. anotherthing is the high octane fuel shouldnt cause the car not to start, seems like whatever they got clogged your filters to me, you could go have a fuel system cleaning done, and all that and if that doesnt work then check into the fuel pump. btw whatd you do to piss them off?

I didn't piss anyone off... 3 words.... Pregnant Ex Girlfriend

Yeah it was the fuel pump.. I changed it. I also had to buy some new spark plugs (NGKs) and everything is back to normal... thanks though man