IPhone Fraudently Blacklisted by at&t

First, chill.  ATT didn’t do this out of spite, they don’t care enough for that.  

You said you have the receipt, are you the original purchaser?    Was it purchased on someone else’s account?  If you bought the phone under someone else’s account and left the account, that account owner still can block the phone.   (For example: you left and didn’t pay the last bill when asked). 

Otherwise take your receipt and phone to ATT and ask them to fix it.  Someone probably entered an IMEI similar to yours wrong and blacklisted the wrong phone.  Remember to be nice, this wasn’t done  by ATT to screw you.

So what model iPhone? If it is a 6 or newer, you have WiFi calling. I guess you already ported your number but you may have had an alternative to that microcell. 

the details:

It is a Iphone 6-64GB

I bought the phone from AT&T and used it myself for 2.5 years until AT&T discontinued my microcell and they refused to offer another (being they discontinued them).  

I have tried WiFi Assist / wifi Calling etc...  calls drop after 1-2 minutes continuously - totally ridiculous

I even bought a special access wifi booster to make certain I have the best wifi on the planet...still get drops.

I increased my wifi bandwidth from internet12 to internet18 just to see if it made a difference -- again same drop calling

all the while I had been calling spending at least 10-15 hours with AT&T customer service to help me....they basically said they cannot.

This is when I decided if AT&T cannot help me I must switch providers.

I did the switch to another and the unlocking of phones was another nightmare, AT&T india call centers are masterful at routing you in circles keeping you on the line hoping for help....but they give none.  They even told me some wild story that they cannot unlock any phones until my next billing cycle?!!!!  even though I own ALL the phone outright, was out of contract, and had no money owed to AT&T.

After many circles and 18 hours later plus chat....I got 1 of 2 phones unlocked (thank god I bought 2 of my other phones unlocked principally from apple store - those had no issues).   

in the end the remaining phone was finally unlocked 6 hours after that...and lo and behold I found that the other phone at another service provider listed as BLACKLIST as Stolen/lost by AT&T

I then looked up the EMEI on other providers to see if they are seeing the same thing....and yes ALL sprint/verizon/T-Mobile/etc  ALL stated I cannot use this phone on their service because it is blacklist by AT&T.  Yet I do the EMEI checker on AT&T and it comes out fine and able to sign up with them?!

I even was able to check with APPLE itself and they came back and told me that I need to go to AT&T store show receipt to get it cleared -- did that...AT&T was less than helpful

I then go to the national blacklist area (thanks to some insider), I was able to get the facts: my phone was listed by AT&T as Stolen/Lost reported by them.  I never had that phone out of my possession nor had I suspended, lost, or reported anything about the phone....I also do not have it insured so I would have no reason to play to that.

I provided the original receipt phone/box etc to the EXACT AT&T store I bought it and they refused to do anything about the issue why its on blacklist.....so what can I do at this point?

i'm blacklisted entriely falsely by AT&T   

and to answer this question stated by another:

 --ATT didn’t do this out of spite, they don’t care enough for that.

It sure seems like someone at at&t had spite enough to do it

Wifi assist is not Wifi calling, it has nothing to do with Wifi calling.  Sounds like you did not enable Wifi calling at all.  

Obviously an error.  Contact advanced support here @ATTCares by PM and send them all your information and copy of receipt, phone number, account number, and even screen shots saying the phone is blacklisted.  They aren’t speedy, but they can help you. 

I know what wifi calling is

wifi assist

settings > cellular > wifi assist (when wifi is poor use cell)  

Wifi calling

settings > phone > wi-fi calling  (this is the one I used to see if it worked better than mcell)

I mentioned I tried every way under the sun...to prove I did all that I could to get better of what I can

I provided link to help, use it.  You won’t get a response till next week at the earliest.