Strong 8K url - buffering

Purchased Strong 8k from Alibaba. Good customer service, gold bubbles and corner logo. But experiencing constant buffering not just live, but vod. It's not my connection as I've had more expensive services working smoothly. Seller has offered me endless alternate url's with no change.

I had one Strong 8k trial that worked well, and then another trial that I didn't test as long and buffered once during the trial. I went with the latter as it was cheaper and had understood that the seller didn't matter as they are merely resellers not re-streamers.

So my question is, do I need a better url? If so which are the better and is there a way to tell? Do url's provided by any seller work with any login from another seller? What should I do/try?