I used to work there years ago and established the
abuse-handling-process. As long as you explain it to them everything
should be fine. The abuse-mails are forwarded to you automatically and
only if you don't respond at all and more complaints keep arriving for
your ip your server could be suspended automatically. They would not
suspend your server for one incomprehensible bogus-complaint, but you
should reply nevertheless reply to keep the counters for the automated
abuse-handling low.
Regards
cxx