To attach files from a repeater to your email message, you need to wrap the file-field with the name of the repeater in the attachments field.
For example, if your form looks like this:
[repeater my-repeater] [file my-file] [/repeater] [submit]
The attachment field should look like this:
You can also show the file names in the email body like this:
[my-repeater] file [my-repeater:index] [my-file] [/my-repeater]
<label>Your Name [text your-name]</label> [repeater r add "Add another file"] <label> Your File [file* your-file] </label> [/repeater] <label>Comments [textarea your-message] </label> [submit "Send"]