What is the average waiting time for decision on ILR made via Sopra Steria Superpriority??

I applied for Settlement via Superpriority on 12 Dec at Sopra Steria Centre @Nottingham Library. Still no decision. Was told will receive email in 24 hours which I never received. No acknowledgement at all of having made application. Called UKVI several times who asked me to wait 5 days before I cou...