Bill increased 280% no additional services

Call them 🤦‍♂️

You have compared previous bills with current?

What line items changed on pricing?

how long were you paying $491? 12 months?

overages charges?

roaming?

hotspot usage?

signed up for business service instead of residential?

Is this concerning a landline or wireless (cell) service?

To answer some of the questions:

• These are 4 business POTS lines. I couldn't find a forum for business.
• We haven't changed over to VoIP because 2 lines are Elevator and Alarm monitoring
• No changes to usage - We are church (worship upstairs, gathering hall downstair - hence the elevator) with only one actual regularly used voice line (a part time office worker and a priest), 1 FAX (which we will most likely cancel now) 
• We have been paying $491 a month for at least a year (bill went up in April)
• I've called twice to ask how we can file a 'dispute' to get our bill back to the lower price and to get the difference between $1377 and $491 credited back to our account. Answer was nothing they can do, because we are no longer under contract. If we go under contract  they can credit back a small amount.
• ATT sales suggested we sign a contract to go to VoIP (significantly lower costs) and that all our lines would continue to work fine. So we signed a contract (in June 2023). Called again to lower our bill and dispute the past charges and ATT rep said there is nothing they can do, because they cannot find a contract that we signed. We are still getting billed $1377 a month and paying it, so that ATT does not cut off our service, they actually sent a letter threatening to cut off service in a week if we didn't pay the bill, which we never stopped paying. 
• Question no one at ATT seems to be able to answer is: We think the fair thing is that we get credited for the $866 difference in price that we have been paying since April 2023 - where and with who at ATT do we formally dispute our bill and present what we think is a resolution?

File a bbb complaint 

https://bizcommunity.att.com/

Thanks @skeeterintexas  - I reposted to the bizcommunity url you provided and received a phone call from ATT rep who will log a ticket (RDS?) to have the extra charges looked at - so at least it seems we are on their radar.

We just received a 400% in our bill.  3 analogue lines-$1,900 a month!!! Get ready. I am writing a letter to the President.  This is usuary and robbery.  The three lines we have serves elevator and fire systems.  No notice on increase, just got a (late) bill.  

@Jacque After 10 months I'm not allowed to discuss the ATT settlement. If I had it to do all over again I would immediately cancel any ATT line that I didn't need and immediately find a different vendor for communication services. VoIP Phone line is about $30/mo. If you have an alarm or elevator line, move to a wireless solution even if the install is a few thousand dollars, it will be a lot less expense and hassle. Note - somehow ATT is not letting me login into my original forum account, so I created another one so I can provide an answer to your comments

We have a lot of business with ATT and if we can't get any consideration, the owner wants all his ATT accounts transferred to another provider.   They'll loose thousands of dollars every month.  Not sure who is making these financial decisions but they are going to loose some loyal customers.