Can my old carrier unblock my phone even though it's not activated?

Today i called sprint and i told them to unblock my phone since the iPhone has already been paid and i have more than 50 days with them so they told me that they were gonna unblock it between 48-72 hours so i moved to cricket the same day i called sprint and cricket gave me a free phone while the iPhone 7 gets unblocked but my question is will they still unblock it even though i don't have my iPhone activated anymore and i moved to another carrier?

That depends on what you mean by blocked!

If it's been blocked on the networks by IMEI then yes they can, though it will take some time for it to filter through all the networks.

If the phone itself has been blocked, then it will need to be turned on and connected to the network, with the number that the network has on record for it - without this they can't unblock it to work on other networks.