First, you might be able to just tap the stop out from the right side if the slide stop does not have enough of a "tab" at top to prevent it from coming out under a little pressure. Then try using a brass wedge to pry the slide up and the stop down, while tapping from the right.
If all else fails, use a Dremel tool with a cutting wheel to CAREFULLY cut through the slide stop between the pin and the thumbpiece so the front part can be driven out. The rear part can then be removed. Do not do this if you get the "shakes" or you will have a messed up gun! With a softer gun I might try to drill out the stop at the pin, but I think those are too hard for that unless you have a carbide drill.
And next time, look through the hole first to make sure the link is lined up, then insert the slide stop with the back part down in the trigger guard. Make sure everything works before swinging the slide stop up and pressing it into place.
And finally, get a fatter link that won't allow the stop pin to be inserted unless it is through the link. Just another way the clone guys have not cared about the details.
Jim