Look mate, we've had some wankers around lately selling shit and ripping people off.
You might be providing a good service, but people are understandably going to be cautious.
Hopefully this will be made more obvious soon, but this is the current rule regarding promotion here:
10- No spamming. If you're caught spamming, you'll be banned for life. No warnings, no second chances. Spamming is also considered when you signup specifically to self promote a thread and your post count is under 10 total. If you have a great opportunity you want to tell lots of people about, stick it into your signature and make real posts. I guarantee that you'll get a lot more interested leads this way, than ruining your reputation on this board in under 5 minutes.
Make more posts, explain your service in detail and If you are genuinely providing a good, honest service then why not accept payment AFTER the service is complete, to re-assure any buyers?
AND DON'T FUCKIN SEND PM SPAM!