Conditional formatting in Matrix Visualisation

[Coldie25]

Hi All, 

I have a matrix visualisation which has data like this: 

It's a tracker to track who've filled in the feedback form for that particular week. 
1 means it is filled while blanks mean they've missed ( No entry is there for that week in my raw data). I just wanna know if it's possible to get blanks to appear as 0 or Text like "Feedback form missed" and 1 as "Filled" 

Please help me with this, if there can be any conditional formatting or anything else which can be done to make my matrix visualisation better. 

Thank you. 

[VijayP]

@Coldie25 

Placing special text thru condiational formatting is not possible as there is already some data is there

[Coldie25]

Is there any other way I can highlight blank cells and add say "0" or "Missing" to them, instead of just blanks, apart from conditional formatting?