To Pawpcorn :
In your opinion, my problem is that for whatever reason, I disconnect then reconnect every 3 minutes with a new IP, so my download/upload information cannot be cumulatively sent to .ru tracker, which updates every 30 minutes. Right?

I don't know what's happening with that 3 minutes-disconnecting thing. But taking your comment as a hint, I thought some DHCP lease time limit may be the problem. I checked it and it was 3600 sec(1 hour) so I changed it to 10 days, but the problem didn't go away.

Also, When I used checkmytorrentip.net and checked if my torrent client IP is changed, it remained same.

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To cannonmc :
Yeah I thought the same too. I thought my IP address won't matter as long as the passkey remains the same. But according to Pawpcorn, that might be not the case.

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To eastonkellen :
If AOL means the some american ISP, I'm not in america.
But I think I have to check if my ISP uses proxy servers. Thank you.

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To Popper :
I'm not familiar with technical terms, but when you say VPN or proxy services, do you mean some program/services to hide the user's IP? If so, I don't use neither of them.

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Somehow, after seeding for more hours, my UL has increased to 628.19MB, but still way below the amount I really uploaded. And my DL still remains 0.00kB even though I did download some non-freeleech torrents.
Well, I guess at least there's a hope..?

Given that no one is having the same problem as me, I think the problem is definitely my computer or my internet service/connection. I'll keep checking what I can do about it.

Thank you guys for so much attention.