I cancelled Project FI yesterday after using it for three weeks. It worked flawless for me but I noticed a >900 MB increase of data usage in a short period of about 24 hours. My accumulated data consumption was 0.15 GB in about three weeks and based on my usage. When I left the house I did not use any internet applications at all, not even e-mail, maps or youtube. My data usage was roughly constant for 3 weeks and I had no complaint about the service at all. While placing a call from my WiFi conenction at home and walking away to the TMO service area the phone did not disconnect my call and when I walked back towards the WiFi access point it seamlessely connected via WiFI witrhout dropping a call uust like stated in the Google Fi service description.
Last weekend I received an e-mail with a warning about the reach of my data limit. I checked my usage and notice a significant increase within a period of less than 24 hours, completely off my standard usage pattern. I opened a ticket with the Google Fi team just to get some standard "blame the enduser" type of answers. The 1st agent explaned me most customers forget to turn off youtube or whatever application they use and that causes the accumulation of my data usage. I was quiet unhappy about that kind of answer and asked to talk to a manager just to find out the manager has basically the same answer and does not even listen to the initial problem.
On my second call I had an agent on the line which continued with the same pattern of answers even though I assured I have not any applications running. I asked to talk to his manager as well. At this point I was already explaineing the situation several times and but this time the manager elaborated and said a possible problem could be my WiFi accesspoint failing, birds may fly through the signal or clouds could interfere with my WiFi signal; rest assured, I lost my faith in the skillset of the Google Fi agent/ manager. I explained he should not worry about my home network, there is Verizon FiOS, a high end CISCO WAP and the WAP is not over subscribed or misconfigured. That statement was probably a highlight for the manager on the phone and he explained me there is a misconfiguration in my nexus 6 and I had to enable "restricted background data" which I did but when I checked my data usage about 20 minutes later I had roughly another 100 MB of carrier data accumulated.
This was leading me to my 3rd ticket on a Sunday evening. This time I spoke to a person which actually looked at the ticket history and after a brief review she called me back and explained a possible issue but left any further details out. I was asked to enable airplane mode when I am at home snd connected to my WiFi access point and if I am not willing to do so I should not expect to get the issue solved.
Long story short, this and previous statements gave me enough reason to cancel my Google Fi service. The cancellation instructions were sent via e-mail and within 10 minutes. I reactivated my t-mobile SIM card the same evening and wait on my confirmation of my cancellation, the conversion back to Google Voice is still in progress at this point.
My conclusion: Either there is a technical glitch Google does not want to admit or there is a magic hand trying to manipulate data usage for a financial advantage.