Date: 201702
Local time of day: 1801-2400
Location: ZTL.ARTCC, GA
Flight conditions: VMC
Light: Night
Aircraft: Large Transport; Low Wing; 2 Turbojet Eng
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Climb
Airspace: Class A ZTL
ATC / advisory: Center ZTL
Reporter organization: Air Carrier
Reporter function: First Officer; Pilot Not Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Communication Breakdown
Second reporter function: Pilot Flying; Captain
Anomaly: ATC Issue All Types; Deviation - Altitude Excursion From Assigned Altitude; Deviation / Discrepancy - Procedural Clearance
Detector: Person Air Traffic Control
When detected: In-flight
Result: Air Traffic Control Issued Advisory / Alert; Flight Crew Requested ATC Assistance / Clarification
Contributing factors: Equipment / Tooling; Human Factors
Primary problem: Human Factors

Narrative: While departing CLT on the ESTRR2 departure approaching DEBIE; we were in contact with ATC on frequency 127.87. We were issued a climb to 30000 feet. We read back the clearance and confirmed the set altitude and began our climb and subsequent level off at 30000 feet. We could hear ATC communicating with other aircraft. We did notice ATC talking to 'Carrier ABCD' multiple times both prior to and after our climb. It should be noted that the controller's diction was somewhat difficult to understand. We received an ACARS message to contact Atlanta center on 125.62. We could still hear ATC chatter on 127.87; however we switched to 125.62 as directed. Upon normal check on 125.62 the controller responded with an unusual response of 'Carrier AECD; where ya been.' I responded with the accurate response that we were on 127.87; we could hear on 127.87; and we're never given a handoff by 127.87. The controller responded 'ok'. She (ATC) issued us a climb and then asked; 'Carrier AECD; who told you to climb to 300?' I responded that the last controller did. I then asked if there was a problem? The controller responded that she controls the airspace above 23000 feet and she had to move an aircraft as we 'just climbed on up to 300'. We were given a new frequency; and upon check on we're given a climb to 38000 feet. Shortly thereafter we were told to phone call ATC during normal business hours. Not clear as to why the event occurred the way it had. We were both monitoring the radio; and cockpit chatter was minimal. We both agree that there was never a controller call in regards to our altitude change after our read back of the original altitude clearance to climb to 30000 feet. No attempts were heard from ATC in any way using our call sign. The controller was slightly difficult to understand; and his transmission strength was less than perfect; but we could follow his calls to other aircraft. We did hear the calls to Carrier ABCD; and perhaps they were erroneously directed towards us; but we had no reason to suspect we were being called. Barring new communication technology; it would be hard to suggest a change. We believed we were complying correctly with all ATC clearances; and were keeping vigilant radio listening. Perhaps the controllers diction could've been clearer.


Second narrative: [Report narrative contained no additional information.]


Synopsis: Air carrier flight crew received a climb clearance to 30;000 feet. The crew received an ACARS message to contact ATC on a different frequency where the Controller stated they should not have been climbing.