Your ISP shapes p2p bandwidth, so I'd say that's why the slow speeds..
Try connecting at different times of the day...
Traffic management Whilst the site is proudly displaying Unlimited there certainly are limits in place
*Size M allowance is 350MB
*Size L - 750MB,
*XL 3GB during peak time and your speeds will be throttled to 128, 192, 256 kbps respectively