Can you please run ping/traceroute using a computer both via WiFi and wired connecton?
Can you also try performing ping tests as well for the following:
We're trying to determine if the problem is with the modem, WIFI connection, or if it's an underlying issue that we may need to raise for further checking.
Please post the screenshots of your results here.
We'd also appreciate if you can provide us with your Customer ID or username via private message.