no reply from dwp ?

hi gordon , i was awarded esa support group for another 3 years back in november 2018 on a paper based decision, so i took your advice and requested a copy of the esa85a and any medical evidence received from my doctor that was used to make any decisions on my claim, i sent this letter on 22december 2018 and had no reply so i resent it registered mail signed for on 20 jan 2019 clearly marked 2nd request, but have still not received any reply, i was thinking the first one was mixed up/lost with all the xmas mail but how long should i expect them to take for a reply to my 2nd request, my name,address, and national insurance ref were on the top of each page , i know the 2nd letter was signed for by dwp on 22 jan 2019. what can you advise me to do next ? many thanks bb.

thank you gordon, can you say what is a suitable amount of time to allow them to reply , eg 14 days or 21 days etc then i will get my wife to call them, many thanks bb .