seedr.cc, bitport.io, zbigz.com, offcloud.com exist to solve exactly this problem. Downloading openly from public trackers is extremely risky. Even private trackers have been known to be monitored by DMCA agencies[0].
How is giving your credit card to these companies any more secure? For all i know they could be selling the user registration data with payment info to some lawyer.
[0] : https://old.reddit.com/r/trackers/comments/4iele6/empornium_...