Why is my data usage spiking so randomly?

I've been scouring the forums for anything regarding data usage spikes, but I haven't seen anyone else running into this specific headache, so I'm starting a new thread. My apologies if this is a duplicate.
I’m using an AT&T mobile hotspot plan with a 25 GB limit. Lately, things have been getting weird with my data consumption. When I check my connection logs on the AT&T customer portal, I see these massive, identical six-digit spikes happening three times a day—say, around 10 AM, 5 PM, and 8 PM. We're talking huge amounts, like 712,213 bytes or something similar (see the attached screenshot). From what I can tell, this only happens when I'm connected via my laptop; my desktop doesn't seem to trigger these jumps at all. I've already tried a clean reinstall of Windows and I'm running Malwarebytes, but nothing is flagging any viruses. I called customer service, but they just told me they have no way of knowing what specific device or process is eating up the bandwidth. I even set my Windows updates to "notify before downloading" to prevent background hogging. Honestly, I'm at my wit's end. Over the last few months, my entire 25 GB allotment has been wiped out by the 5th or 10th of the month. If AT&T wasn't reporting these exact numbers, I wouldn't even know what to say, because the usage they show is definitely much higher than what I actually consume while browsing. Has anyone dealt with something like this? Any idea what could be causing it? Thanks!

http://postimg.org/image/ri4m6g4gn/
http://postimg.org/image/62mvh4azt/

Hey, do me a favor and send over a screenshot of your processes first. Just hit ctrl+alt+del—>task manager—>processes. Or better yet, just kill off any weird stuff if you spot anything sketchy, then let me know 👍

http://postimg.org/image/ckthecvxx/

Look at this. 😲 I used CCleaner yesterday to tweak my startup settings so that nothing runs when I boot up except for my antivirus. It’s a complete mystery to me why some process would be draining the exact same amount of data three times a day.

wanderingeagle27 said:http://postimg.org/image/ckthecvxx/

Man, I don't get it. Yesterday I used CCleaner to tweak my startup settings so basically nothing runs except my antivirus. It makes zero sense why the hell I'm still seeing the exact same amount being drained three times a day. 😲

Look, try running a scan with Malwarebytes to scrub out any malware, and double-check that you don't have some random auto-update running in the background. Let me know what happens.