We got the top pole back to front..how to separate the poles ?

push on the back board up to get it to lock. Use the catch plate to bring it down.

The locking teeth or retention spring, if equipped may be damaged and blocked.

I would clear any loose debris, repack around pole with a dry concrete mix then add water to it make sure pole is level, brace if necessary and give 24 hours to set up.

take it to the store or true it off and take the wire then put it back and then try

You need to give us a better picture and description of your problem. It looks like you are working with a basketball goal that is laying down on the ground. Do you really mean only the "Net," or are you using the word net to mean the whole backboard mechanism? Are you talking about hooking the strings of the net to the orange "hoop?"
Is this the first time you have tried to raise it, or has something changed after you have used it successfully for awhile? Is this new and you put it together yourself? If so, you probably made a mistake. Review the instructions, or ask a mechanical friend to look at it.
Often the answer is easy - its asking the right question that is the hard part! Hopefully you can understand that you have not yet asked us the right question.