Phone activated but not working

I purchased an unlocked phone, and ordered a prepaid ATT SIM card online. I chose the $25/month special if you prepaid $300 in advance. I chose the option to port my old number and filled out the required information.

I received the SIM card via FedEx, and installed it in my new phone. (The packing sheet showed the wireless number to be my old number, i.e. the one I am porting.) Following the instructions that came with the SIM card, I called 866-975-0050 to complete the activation (this was Saturday evening). The person I spoke with said the department that handled porting was closed until Monday, but in the meantime he could activate my phone with a temporary number. On Monday I should call back and they could handle the porting.

Let me say at this point I had never received any emails from ATT other than relating to shipping my SIM card. I checked my credit card online, and it showed the $5.29 charge for the SIM card, and a $0.01 pending charge from VESTA (which I determined is the prepaid account). But I had no other confirmation that I received the $25/month special. I explained all this to the rep, and after a lot of confusion on his part, he said he believed they wouldn't charge the $300 until the phone was actually activated.

So I read off my ICCID and IMEI, the rep did a bunch of typing, then he came back and said we're all set. He told me to make a call using the code "*123*zipcode*21#". He said this was for the $50/month plan, which I was getting for $25/month.

After ending the call with the rep, I sent the code from my new phone. A bunch of messages flew by, including something with the new (temporary) phone number. It disappeared before I could write it down. Then a message said to power off the phone, wait 10 minutes and then turn it back on, and I would receive a text indicating the phone was now activated. I did as instructed and powered the phone back on an hour later, but no text, and apparently no service.

This morning I checked again, still no service. Under the Android phone status screen, for "My phone number" it says unknown. As a last-ditch effort, I found the "ATT Prepaid Activation Portal" and entered my information again. I got the response "GA701 : Oops, we hit a snag while activating your device. Come back later and try again."

Can anyone shed any light into what is going on? I had no idea this would be so complicated?