"Measurement" causes collapse, correct? What is different about measuring the system in a way that forces how the system collapses versus a way that results in a random result?
Does the other entangled system yield random results if you try to force the collapse of its entangled sibling?
Can you describe some experimental setups? I'd like to know how we found that out.
The operation you are depending on to communicate doesn't exist.
It's a bit weird that you can choose to read UP/DOWN and your counterpart can read LEFT/RIGHT, or even a bit of both by reading at an angle, but you still can't move classical bits around that way, because you can't read "RIGHT". If you do fiddle with things to force a result, the fiddling will erase the entanglement, because under the hood, in math, those two things are basically equivalent statements. If you do force something, your forced result will have no bearing on what your counterpart gets; if you force "RIGHT" all that will happen is that your counterpart will still get a 50/50 in the LEFT/RIGHT basis. You didn't communicate anything.
You can nudge it in a couple ways, and you can statistically predict what may happen as a result. However, none of the ways you can do that result in communication, because you can't get around the way you can't choose the collapse. There is no way to communicate because you can't force the decision. If you do force the decision you break the entanglement.
I think this is one of the main errors people make on this matter; you hear "ah, if mine is "up" then theirs is "down" automatically, so surely if I set mine to 'up' then I can communicate with them?" But you don't get to "set" it. You have no choice in the matter. It just happens. In communication, you are ultimately communicating your choice to have a 0 or 1, and you can't communicate when you have no choices to make. In more classical terms, it'd be like me trying to send you a message with next week's lottery numbers. I can't; I have no control over those numbers. (Not a precise analogy since there's no "quantum" there, but I think the intuition is reasonable.)