[OT] Spam filter woes [was: mailing list down ?]

For the last fortnight or so, all [maxmsp] and [pluggo] mails have been getting filtered out by my webmail's spam filter.
I have reset the filter several times, and tried to train it with dozens of messages. I have made several calls to my ISP, one of which seemed to have had temporary results, in that things went back to normal for a couple of days.
However, as of Sunday, things have gone tits-up again, and this time my support calls are being answered with "it's not our fault - refer to the sender".
Has anyone else (particularlry BT Yahoo customers) had this problem ? Is there anything that can be done at the list end or do i have to turn the filter off and be bombarded with scams & penis enlargement products ?
cheers
Roger