NETGEAR C3000-100NAS single digit speeds after upgrading xfinity speed from 100 to 200 mbps

[Sara112978]

I upgraded my xfinity speed from 100 mbps to 200 mbps and my netgear modem speeds dropped to 6mbps download and 2mbps upload speeds. Xfinity said it was a netgear issue and when I called netgear samuel in India said I needed to renew my warranty for him to fix the issue. What kind of customer service is this? I feel completely conned. My device says it should be able to handle speeds up to 300.

Then sam in India said I could figure it out and do it myself by looking in the community forums. But he couldn't answer any questions about specifics!!! Seriously shameful customer service. I don't see anyone else with a similar issues here. Is this an easy fix? Does anyone know why this is happening?

I will never purchase another netgear item again with these kinds of ethics. Before you buy I hope you read what current customers are dealing with.

[FURRYe38]

Please post a copy and paste of the modems connection status page.
Have the ISP check the signal and line quality UP to the modem. Be sure the ISP provisions the modem correctly.
Be sure there are no coax cable line splitters in the between the modem and ISP service box. 
Be sure your using good quality RG6 coax cable up to the modem. 
Be sure to power OFF the modem for 1 minute them back ON.
https://community.netgear.com/t5/Cable-Modems-Routers/General-info-and-Troubleshooting-for-Cable-Mod...

[Sara112978]

This was the speed I was getting after upgrading to 200mbps.

[Sara112978]

This is the speed I'm getting now after downgrading back to 100mbps. Its still awful. I have already had ISP check signal line quality its fine. The ISP says there is no problem on their end. I spent 4 hours with them on the phone yesterday. The modem has been restarted like 7 times at this point. Does not make a difference. The modem is hooked up directly to the wall. Do you have any suggestions?

The netgear tecg support said he could fix it with remote access and me paying a warranty fee, so I think its something else that needs to be done than these suggestions. Can you think if anything else?

[Sara112978]

This is the speed I'm now getting. Worse than dial up. Can someone tell me why this is happening?