Hello Sandra,
data = Import[
"<your path>\\Plot_W3234-3240.csv"];
EstimatedBackground does not support data in the form {{xi,yi}...}, but can handle TimeSeries
ts = TimeSeries[data];
Off[InterpolatingFunction::dmval]
ListPlot[{ts, EstimatedBackground[ts], ts - EstimatedBackground[ts]},
PlotRange -> All, ImageSize -> Large, Joined -> True]
ListPlot[{ts, EstimatedBackground[ts], ts - EstimatedBackground[ts]},
PlotRange -> {{0, 20}, Automatic} , ImageSize -> Large,
Joined -> True,
PlotLegends -> {"data", "background", "corrected data"}]