The group called People Vs Spark Sport announced on their Facebook page that they will file a class-action lawsuit against Spark Sport (Spark New Zealand).
It would claim Spark "has misled its customers about its Spark Sport product/s and acted in a manner that aims to deceive its customers and shareholders."
Customers took to the Spark Sport Facebook page and on Twitter to express their frustrations, among them TV1 broadcaster Hilary Barry - which was quickly resolved.
"Mr B's infuriated by these three dots during his rugby coverage but I've told him it's a lovely time for us to talk. And talk. And talk. Oh now it's just gone to black."
However, there had been a significant decline in customers needing assistance for glitchy streams, Latch said.
"The number of customers engaging via our Care channels declined almost 80 per cent between the first and second weekends and fell a further 27 per cent last weekend.
"Furthermore, 86 per cent of customers receiving care have only contacted Spark Sport once during the tournament, indicating that we've been able to promptly assist the large majority of customers."
Additionally, 198 customers had taken up an offer for a complimentary Freeview SmartVU device as an alternative way to watch.
These were in cases where the telco's technicians had established it would likely be helpful to their particular issue, Latch said.
The best solution for customers depend on a range of factors, including their broadband connection, in-home connectivity and the devices used to stream matches.
"Our in-home technicians have found that for the most part, issues have been related to in-home technology or device setup (such as WiFi quality and/or configuration)," Latch said.
"We're pleased we have been able to help many customers achieve a much better viewing experience.
"That said, we acknowledge some customers are still having issues and we understand their frustrations in wanting to have a better viewing experience for such an important tournament to all rugby fans."
He reiterated customers who still encountered issues with their stream should contact Spark Sport.
As of Wednesday, there had been over 186,000 Spark Sport subscriptions for the Rugby World Cup Tournament Pass.
However, Spark had not said how many were paying customers and how many received it under a qualifying Spark plan.
It had also continued to grow throughout the tournament, outweighing cancellations four to one since the New Zealand and South Africa match.