Att helped me unlock my used but new to me cricket moto pure sim won't work still

At&t cannot unlock a cricket phone.  Only Cricket can.  Carrier unlocking a phone will allow it to work on compatible carriers. You didn't say what carrier you're trying to use the phone on or whether or not you have checked with that carrier to see if the phone is compatible with their service.

Okay I have a cricket Moto g pure which I talked to AT&t customer service whenever I ordered my SIM card and they said it should be good to go and yes it's compatible it's not blacklisted so on and so forth and it should be good to go as soon as I get my sim well now here we are

Please refer to my previous comment. Your phone is not unlocked.

You need to have Cricket unlock it.

AT&T locked phones will work on any of its mvnos. But the reverse is not true. Phones that are locked to an AT&T mvno, including cricket, will not work on AT&T until they are unlocked. They can only be unlocked by the mvno. AT&T can only unlock AT&T phones.

Exactly.  Yes AT&T said the phone is compatible and will work.  But that's all they can tell you.  Now it's up to you to get the phone unlocked through Cricket.  AT&T would have no knowledge beforehand about whether it's unlocked or not, only that the device is generally compatible. 

That's two different things.  You're only half-way there.