We can use spamassassin and make the ip or domain name in black_list from where those spams are coming, to prevent those spams.
Also use mail filters and write proper rules to filter those spams.
Make her default address set to :fail: or :blackhole:.
Add that ip(spammer's) in exim_deny.
Set rule in iptables to deny that IP from access of port 110.
Post mails to spamcop and others reliable source, informing about the spams with all the header.