The VPOP3 spam filter has a "whitelist" facility so that you can specify email addresses which will never be blocked by the spam filter.
Go to Settings -> Spamfilter -> White/Black Lists, and choose the Whitelist Addresses tab.
In the Entries to add box, type the email address(es) you want to add to the whitelist. If you add multiple addresses, put each one on a line of its own.
You can specify a full email address or use wildcards (eg *@example.com), or use regular expressions if you wish (by surrounding the regular expression with / characters).
For the full documentation, see the online manual.
(NB - if an address is also in the spamfilter "blacklist" then they may still be blocked, depending on the relative weights of the whitelist & blacklist)