We know that TT was a pizza delivery guy, but it's not specified who he worked for:
from:
http://www.cnn.com/2013/04/21/us/tamerlan-tsarnaev-timeline
If he did work there, then maybe the order, with the address, for three different types of meat (meatballs, a chicken cutlet and a side order of sausage) was really just a message that the job was complete.