The pricing info is confusing and maybe inaccurate(?)

It says:

Up to 500 emails / month 100 tests emails/month | 50 emails/day 100 test emails/day 50 emails/day

That's a bunch of conflicting info. I'm not sure what the actual limits are.

It also says "Remove watermark" in the free tier, but "No watermark" in the paid tier... what's the difference between those? Seems like you can have no watermark in either tier?

Finally, do you use dedicated IP addresses for sending? If so, how do you keep your IP reputation clean? What if a spammer signs up and sends thousands of spam emails - will my email sends also be affected because we share the same IP?