"また"+"今度" can be used to indicate a specific time you will do something again.
For example, if you played soccer last Saturday and during the week a friend asks what you are going to do this weekend, a conversation could go like this:
A: 今週末、何をする？ (What are you doing this weekend?)
B: また今度の土曜日にサッカーをする。(I'm going to play soccer again this Saturday.)
Note, if I was going to be technical, that there is a difference between using the words "また" and "今度" together and using "また今度" as an idiom. My guess is your friend is talking about "また"+"今度" and not "また今度". It is certainly possible that the idiom doesn't make sense in his/her region and dialect.
So in your friend's region, this usage might be the expected usage and not the
idiom usages in this question or this question.
For reference, I lived in the 甲信越 region for 4.5 years and have been living in the 東京 area for over 3 and both usages are acceptable.