A CPR MDT COULD NOT MAINTAIN ALT IN HVY WX.

Narrative

WE WERE CLRED TO 10000 FT; RADAR VECTOR HDG 180 DEGS; WHICH TURNED US DIRECTLY INTO A TSTM. WHILE DSNDING TO ALT; I MADE 6 OR 8 CALLS TO CTR ASKING FOR DEV TO THE R AND REQUESTING LOWER. CTR NEVER RESPONDED TO ANY OF OUR XMISSIONS. AN ACR RESPONDED TO OUR CALLS BY TELLING CTR THAT WE WERE TRYING TO CALL THEM AND GET CLRNC TO DEVIATE FROM HDG AND ALT; BUT THAT STILL DIDN'T GET CTR'S ATTN. THE FREQ WAS VERY CONGESTED; SO I'M SURE THE CTLR WAS DOING THE BEST HE COULD DO. WE WERE EXPERIENCING TURB DURING THIS WHOLE TIME. HOLDING ALT AND HDG WAS EXTREMELY DIFFICULT. A HVY DOWNDRAFT TOOK US DOWN ALMOST 1000 FT ABOUT THE TIME CTR CONTACTED US. INSTEAD OF ANSWERING OUR REQUEST; HE SPOKE HARSHLY ABOUT OUR ALT AND HDG AND HANDED US OFF TO THE NEXT CTLR. AT THIS TIME WE WERE CLRED FOR LOWER; AND WERE STILL IN WX; BUT PAST THE HVY PART OF THE TSTM AND PROCEEDED ON TO THE LNDG AT CENTENNIAL. THE CAPT CALLED CTR AND SPOKE WITH THE SUPVR. THERE WERE NO CONFLICTS WITH OTHER TFC; WHICH WE ALREADY KNEW. HOWEVER; WE FELT OUR CALLS WERE NOT HANDLED IN A TIMELY FASHION AND THEREFORE PUT US INTO A WX SIT THAT COULD HAVE BEEN AVOIDED. CONGESTION ON THE FREQ AND WX WERE THE 2 MAIN CONTRIBUTING FACTORS GOVERNING THIS SIT. THE CAPT DID WHAT HE COULD TO MAINTAIN ALT AND HDG UNDER RATHER TURBULENT CONDITIONS. CTR COULD HAVE RESPONDED TO OUR CALLS AND GIVEN A SMALL DEV TO THE R AND/OR A LOWER ALT ASSIGNMENT WHICH WOULD HAVE RESULTED IN A SMOOTHER TIME FOR ALL.