Should i consolidate or deal with each agency separately?

About 6 years ago i lost my job and was unable to pay off 2 credit cards. I went back to school and never held a steady job until now. Through those years the collection agencies tried to contact me but all i did was ignore them. Now that i have a well paying steady job i want to get rid of the debt. Should i seek consolidation or deal with each collection agency seperatly? Also, does the interest continue to add to my debt? Does the amount of my debt continue to grow as the years p?