CL-600 DEPARTING MLB CLBS TO INCORRECT ALT.

Narrative

AFTER DEP FROM MELBOURNE; DAYTONA APCH CLRED US TO 10000 FT. SHORTLY AFTER; THEN CLRED TO 15000 FT AND CONTACTED ORLANDO APCH. AT THE TIME; I WAS TALKING ON #2 RADIO TO COMPANY WHEN THIS CLRNC WAS ISSUED; AS MY FO ANSWERED IT. WHEN I RETURNED FROM TALKING TO THE COMPANY; MY FO ADVISED THAT WE WERE CLRED TO 15000 FT AND GOT A FREQ CHANGE. A FEW MINS ALTER; ORLANDO APCH CALLED US; ASKING IF WE WERE ON FREQ. MY FO ADVISED ME THAT HE HAD FORGOTTEN TO CHK IN. I ANSWERED ORLANDO TELLING HIM 'ACFT X CHKING IN; CLBING OUT OF 12000 FT FOR 15000 FT.' (AT THE TIME WE WERE CLRED DIRECT TO THE ORLANDO VOR.) HIS RESPONSE WAS 'TURN R HDG 330 DEGS AND JOIN J53 N OF ORLANDO.' LATER; WE WERE CLRED TO 230 DEGS AND TOLD TO CONTACT ZJX. WE WERE CLRED TO OUR FINAL CRUISE ALT AND PROCEEDED TO ATLANTA. UPON ARR IN ATL; WE WERE TOLD TO CALL ORLANDO APCH. THE CTLR SAID THAT WE HAD CLBED TO 15000 FT WHEN WE HAD ONLY BEEN CLRED TO 14000 FT. HE SAID THAT THERE WAS NO CONFLICT WITH ANY OTHER ACFT BUT ABOVE 14000 FT WAS CTLED BY ZMA AND THEY HAD CALLED TO INQUIRE AS TO WHY THERE WAS AN ACFT IN THEIR AIRSPACE. I TOLD THE CTLR THAT IT WAS MY UNDERSTANDING THAT WE WERE CLBING TO 15000 FT AND DID NOT RECALL BEING CLRED TO 14000 FT. HE SAID THAT HE HAD CHKED THE TAPES AND THAT DAYTONA HAD ISSUED OUR CLRNC TO 14000 FT AND THAT 14000 FT HAD BEEN READ BACK. WHEN WE CHKED IN WITH ORLANDO; I TOLD HIM THAT WE WERE CLRED TO 15000 FT. HE CAME BACK AND CLRED US TO JOIN THE AIRWAY N OF ORLANDO. NOTHING WAS SAID ABOUT MAINTAINING 14000 FT. WE WERE LEVEL AT 15000 FT FOR NO MORE THAN 1 MIN WHEN WE WERE CLRED TO FL230. AFTER TALKING WITH THE ORLANDO APCH CTLR ON THE PHONE; HE SAID THAT HE HEARD ME CHK IN CLBING TO 14000 FT AND TOLD ME TO MAINTAIN 14000 FT. MY FO AND I NEVER HEARD THIS. WHAT WE DID HEAR WAS THE HDG TO JOIN THE AIRWAY AND; AT THE TIME THE FREQ WAS VERY QUIET; ELIMINATING THE POSSIBILITY OF BEING STEPPED ON. WHAT CONFUSES ME IS IF THERE WAS A CONFLICT OF OUR ALT WHEN I CHKED IN; WHY WASN'T I CORRECTED IMMEDIATELY? WHY WERE WE ALLOWED TO LEVEL AT 15000 FT WITHOUT ORLANDO QUESTIONING OUR ALT? WHY WASN'T ANYTHING SAID THE ENTIRE FLT WHEN I ASSUMED THAT EVERYTHING WAS NORMAL? MY PERSONAL FEELING IS THAT THE CTLR DID NOT LISTEN CAREFULLY TO MY READBACK AND DID NOT CATCH THE ALT DISCREPANCY UNTIL ZMA NOTIFIED HIM OF AN AIRPLANE IN THEIR AIRSPACE. I HAVE BEEN FLYING COMMERCIALLY FOR 17 YRS AND AM VERY AWARE OF ALT AND CALL SIGN READBACK. THIS IS THE FIRST TIME THAT I HAVE EVER EXPERIENCED A SIT LIKE THIS.