Been having my email to customers trapped by their servers' anti spam filters. Getting worse lately--

So what to do? Been spending way too much time online trying to figure this out, so far I've found:

some of my email server's IP addresses- first 2 numbers are static, last 2 numbers are dynamic-- have been flagged by Spamcop.net. But running those IP addresses thru Spamhaus/Cisco/Talos shows no problem with them--

However, Spamhaus/Cisco/Talus shows my ISP IP address as "poor reputation" and goes on to explain the high-rates of spam mail associated with my IP! Yet Spamcop says nothing wrong with it...

According to Spamhaus my ISP IP is on the PBL list, but not just mine, it's a whole block of 73.3.xxx.xxx addresses. I've had the same domain host (Ipage) and email addresses for YEARS...

Just wondering if anyone else has had to deal with this nonsense? I'm going to be giving Comcast a call shortly, and see what they have to say. Will they simply provide me with a new static IP, or?