I used to use premiumiptv.co for my IPTV needs but UK ISPs were blocking it and they didn't support VPNs so I decided to look elsewhere. I put a message out on /r/iptvresellers and I get a message from olganet1983 about his service and it fit what I wanted so I got a trial and all seemed well. I sent the money and received the m3u promptly.
The service worked great with the VPN and was barely getting any lag for the first 2 weeks. After 2 weeks however, the channels suddenly stopped working and I messaged him to troubleshoot the problem. I've been through the usual checklist of problems (different devices, change VPN, 4G and WIFI etc) to no avail. Every now and again, Sky 1 comes available but then it goes down a couple hours later. The server doesn't even seem to be reachable so I asked for a refund for the rest of the time I have left. He has yet to answer me but he's still actively selling on /r/iptvresellers with the same email. I'm just going to chalk this up as one of the risks but hopefully this review will help others.
Edit:
premiumiptv.co has sorted me out with a free month and the new line they gave me works great with my VPN! They were always a professional outfit and the problems I was having were on my side (I was able to watch on my 4G device but not on WIFI). Been with them for over a year and thoroughly recommend them!
The fact that this reseller posts way too often rings alarm bells, unfortunately, it appears that the more a seller advertises the worse there service is you just have to read through the subreddit to see that.