2007 Fantom Cross rider here. I use toe clips on all my bikes, with MTB shoes with no cleats. I never tighten straps, but like the security of the "cage" to keep my feet securely on pedals. Your technique may be the issue, but shoes with rough tread pattern might help. You could tighten the straps, but then you have to remember to loosen one before stopping. Sounds like you are pulling up on pedal, in which case tighten straps or go to "clipless" pedal and shoe system.