Want to retrieve/display client visit dates by client name

I want to be able to type a client's first and last name in a cell in one sheet, and have it pull/retrieve from another sheet all dates the client has visited my clinic. This other sheet is an exported file from an online scheduler I use. It is less than elegant and cannot be customized.

I've provided a sample workbook for an idea as to what I am trying to achieve. Invoice sheet requires client first and last name (E8). B10 service date field needs to be populated with all the dates he/she has visited. The rest of the information can be static, but it would be nice if it automatically populated too.

I came up with this formula but it's not working:

=IF(ISERROR(INDEX($C$2:$N$400,SMALL(IF($C$2:$C$400=$Q$4,ROW($C$2:$C$400)),ROW(1:1)),2)),"",INDEX($C$2:$N$400,SMALL(IF($C$2:$C$400=$Q$3,ROW($C$2:$C$400)),ROW(1:1)),2))

From the attached images below, I want to be able to type "Jill Green" in the Claim#/Client Name box, and have all the dates she's visited display under SERV.DATE below.

Thank you.