This all could have been prevented if you would have just said in the title [Free Slots Available] instead you misused the word 'Free' in my opinion, Also i think you overdid the 'Tip asking' part. You made it clear regarding the tip in your original post so why ask every time you accelerated for someone? I consider that begging.
No, nothing would have been prevented as this guy is a known ban evader, troll, and to a certain extent, a scammer. Read the reference rating on him, and his previous account(s).
If someone has done some work, it no begging at all .
You are leaving negative ratings to people who say they will tip, but don't end up doing so. Therefore, your service is most definitely not free.