Need help removing blanks from a join collect formula

Hi,

I'm trying to use a join collect formula that referencing a column in a helper sheet.

=JOIN(COLLECT({Column I Want Data}, {Reference Number}, [Reference Number]@row), ",")

It's pulling everything from {Column I Want Data}, that matches the [Reference Number] with {Reference Number} on the helper sheet and any cell that is blank will return these commas" , , , , , , , , , , , ," how can I edit my formula to ignore the blanks that are in {Column I Want Data}

1st image is the one with my formula, you can see the commas, where a cell is blank

2nd image is how the data looks in my helper sheet