Over the last few days, my news feed will show folks are sending me boosts (both energy and stamina) but they are not being registered so that I can use them. Both will show that I'm now at 0/5 but my account is not receiving anything new.
Make sure you've accepting them from the Mobsters alert menu if you don't click accept on them here you cant use 'em
Also, check if you already have 5 of 5 Energy/Stamina boosts. You can only hold a max of 5 so if you are full then you will be unable to receive anymore until you use one.