Here's a mid-thought observation: your IPTV Reseller Panel runs on a server somewhere. That server has a timezone. If it's not your customers' timezone, you have a problem. I've watched a British IPTV reseller schedule a promotional launch for midnight GMT. His panel used EST. The launch happened at 5 AM GMT. Customers who stayed up for the deal felt tricked. He didn't realize the mismatch until someone tweeted a screenshot of his panel's timestamp. Embarrassing and avoidable.
The pattern that keeps showing up is scheduling drift. A serious panel lets you set customer-facing timezone separately from server timezone. It also shows you both clearly. Run a British IPTV test account through your panel. Schedule an expiration for 11:59 PM GMT. Watch what time the panel actually cuts access. One reseller I know discovered his panel was four hours off because the provider never configured daylight savings correctly. He switched to a panel that uses UTC internally and converts to local for display only. That IPTV Reseller Panel now handles his entire operation without a single time-related complaint. That said, this sounds minor until a Black Friday launch fails. Then it sounds like a catastrophe.