display string array content in textbox

I am using mlreportgen.ppt to create a powerpoint using matlab from a template powerpoint.

I want to add slides with bulletpoints into a textbox. The bulletpoint content comes from a string array (45x1) converted into cell array (1x3). In each cell there are 15 strings aka. 15 bullet points.

Using a for loop I am trying to add a slide template and the bulletpoints.. however I am not getting the array contents in the textbox.

for i=1:length(text_cells) %text cells is cell array
    txtslide = add(slides,'blank text')
    contents = find(slides,'text box')
    
    textmain = ({'following was found: ',...
        text_cells(i),...
        'carry on --> '});
    replace(contents(i),textmain)
end

the picture below shows what I am getting currently with my code: CAN ANYBODY HELP ME?