DAX Code PowerBI - Rolling Average Required

Hi. Still a beginner at DAX so any help would be much appreciated. I'm trying to get a rolling average of Product Distribution, but when I use the DAX codes I can find online for rolling averages, it creates an error as the date column contains duplicate dates. The code I'm trying to use is;

Product X Rolling 4Wk =
VAR NumDays = 28
VAR RollingSum =
CALCULATE(
SUM('Raw Data'[Product X In Store?]),
DATESINPERIOD('Raw Data'[Call Date],LASTDATE('Raw Data'[Call Date]),-NumDays,DAY)
)
RETURN
RollingSum/NumDays


Example of type of data is as follows. We show this as weekly average % distribution currently, but client has requested visibility of 4 week rolling average.


Call Date Store Name Product X In Store?
06/09/21 Store A 1
06/09/21 Store B 0
06/09/21 Store C 0
07/09/21 Store D 1
07/09/21 Store E 1
07/09/21 Store F 1
08/09/21 Store G 0
08/09/21 Store H 1
08/09/21 Store I 0


Any help would be greatly appreciated!