Take it back and start new if that’s what you want.
I wish I saw this thread earlier. I have a bio cube 32 and a cornerflow tank with a sump. I started with the bio cube. The less amount of equipment you have the less you take advantage of and Apex. On a new tank, it’s not helpful to chase parameters and within the first six months that is what you will do (in general). Sometimes all that info is not a good thing. If you wanted to keep the biocue simple, which you can and grow sps, you can and I do. I connected an Apex to my 65. As mentioned the more equipment you have the more the Apex or a similar controller becomes useful. If you have an Apex and are out of town but don’t have anyone in a position to do anything at the house while away, well, having the notification does not matter in that instance. Eventually I connected the Apex to both tanks for feeding and maintanence. If you keep it simple you will not take advantage of it with the exception of notifications and simple stuff. If you decide to go bigger with more equipment (I don’t always think bigger is an upgrade like some think) you can use it down the road.
In regards to the probe not working, if it was dry when you got it, it can be damaged. Sometimes the cap leaks, there should be water in it to keep it moist.