Urgent: ISP detection failing for my web tool!

i'm completely stuck, guys, and i'm hoping someone here has faced this before. for the past few days, our 'What is My ISP?' web tool has been acting up massively, and i'm pulling my hair out trying to fix it.

the main problem is that our isp detection is just... failing. not for everyone, but for a significant chunk of users, especially those on mobile networks or using vpns. instead of showing their actual internet service provider, it's either returning 'unknown', a generic hosting company name (like amazon or google cloud, which isn't their ISP!), or just flat-out timing out. this makes our core feature, the actual ip address lookup for isp, totally useless for them. it's super frustrating and we're getting reports.

i've tried everything i can think of. we've cycled through a couple of different third-party geoloc/ip APIs, thinking maybe it was an issue with the provider. i've even tried doing manual `whois` queries for some of the problematic IP addresses, but even those often just point to the datacenter or a very broad region, not the actual ISP serving the end-user. nothing seems to work consistently or reliably. i even tried caching some results for known ranges, but that's just a band-aid.

here's an example of what i'm seeing in our logs when it fails, it's just so unhelpful:

[2023-10-27 14:35:01] INFO: IP 192.0.2.1 (user-agent: mobile_chrome) - Detected ISP: UNKNOWN
[2023-10-27 14:35:05] WARN: IP 203.0.113.5 (user-agent: desktop_firefox) - API Timeout for ISP lookup.
[2023-10-27 14:35:10] INFO: IP 198.51.100.10 (user-agent: mobile_safari) - Detected ISP: Amazon.com, Inc. (AWS) - (Expected: T-Mobile or Verizon)

i'm desperately seeking advice on this. are there more robust isp detection methods i should be looking into? or am i missing some common pitfalls when it comes to mobile ips or vpn traffic? any insights on how to get accurate ip address lookup for isp data would be a lifesaver right now. we need to fix this asap.

thanks in advance!