Hmmm, that was a rather terse reply from them.
I agree that the DMC4029SK4-13 seems to be a likely match. It’s a complementary MOSFET pair with the right package, and the “C04” portion of the marking on your part is typical of 40V complementary MOSFETs. However, the part marking is not the same, as shown in the DMC4029SK4 datasheet (see below).
It’s possible that their part is a privately labeled version of the same part, or that it comes from some other unidentified manufacturer as a clone of the DMC4029SK4. Hard to say. In any case, if you’re just trying to revive something rather than throw it away, it seems like the DMC4029SK4 is a reasonable option to try.
As an FYI, here are all of the complementary N/P channel parts in stock today that are of the same package type and rated for at least 40V.