This freelancing buyer has not paid my commissions. Can I get back at him?

[kumar]

I am working as a freelancer and getting my projects thru a freelancing site odesk.com. Last month, I worked on an Email Marketing project with a buyer who promised commissions on per email sent,with a bonus per response generated and cliet made, apart from an hourly base.

After two weeks of working, I checked with him on the commissions for the mails I had sent (the mails could be tracked thru the Web Outlook Access or Salesforce.com which contained the database of leads). He only responded after the third week had passed (even though he was always online on Skype) and told me that there was some miscommunication and that the commissions on per email sent was ONLY for the first time contact to a lead and not follow up mails to the same lead(As per his instructions, I was supposed to send 2 follow up mails to each lead if the lead didn't respond the first time round). This after working for three weeks and sending him weekly reports containing all the numbers.

When I reminded him of our agreement, he reluctantly asked me to send an excel based invoice containing 2 pricings, one charging for all the emails sent and the other, charging only for first mails sent to each lead (i.e. excluding follow up mails). There was a difference of $290 between these pricings but I still sent him the invoice with both these pricings. The only time I heard from him after this was his confirmation that he received the invoice and was 'looking' into it. I have left numerous skype messages and emails but he never responded (He is online even now as I write this). I stopped working on his project and complained to odesk and as expected, they said they only guarantee hourly rates.

As for documentation, I only have the project description on oDesk and our skype chats to prove that I was to be paid commissions. What's really disgusting is that this buyer, based in Ontario, is a high profile serial entrepreneur. Incidentally, he is also the CEO of the Canadian branch of an Indian based company. I am trying to contact the Chairman and CEO of the parent company which is based in the neighboring state (to where I live), however I am not optimistic, since the project I did was for a different company based in Canada (and listed on the Canadian Stock Exchange) in which this guy is a senior partner/investor. I really don't want to let go off my commissions partly because its a big amount for me (around $850) and mostly because of the way I had to slog, looking after my mom in the day who was hospitalized at that time and working on his project at night.

Is there any possibility of getting my commissions? Even if I don't, I don't want to give up without a bloody fight.

[kumar]

I just realized that I have made the above post unnecessarily long with all small details. Sorry about that!