How can I modify my array TEXTJOIN formula to output only unique values

This is my worksheet:
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This is the formula in question:

=IF(C3<>C2;TEXTJOIN(", ";TRUE;IFERROR(IF(SEARCH(E3;E:E);I:I;"");""));"")

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My goal is to collect all markets in column I that belong to the same Invoice number, into one cell in column J.
I made this wildcard array TEXTJOIN formula that does everything that I want it to do, exept that it outputs all the values it finds; when I want it to only output the unique values.

Desired results:
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How can I modify this formula to accomplish this?