Uploading.com is a scam site.

I was with them in 2009 and earning good and managed to sell tons of accounts for them. Then suddenly the company changed hand and new rules applied and I was not so actively promoting them. Then again, they changed/revised the referral rate from 10% to 20% of total referral earning. And they only paid me 10%. I started an argument with them on why I was treated specially. They finally gave me 20% but only earning after mid of April are counted. Then one of my referral made tons of sales amounting to thousands of dollars. Again, Uploading.com didn't pay me a cent. I raised that with them and guess what? They said my referral signed up with pay-per-download and later switch to pay-per-sale, and since he signed up with pay-per-download, I am only entitled to his pay-per-download earning! I pointed out that:

1) Their website clearly stated that I am entitled to 20% of the total earning from my referral.
2) My referral signed up way back in 2009. There wasn't any pay-per-sales yet
3) When someone switch from pay-per-download to pay-per-sale, he will not be paid for the downloads generated from his files, only sales are counted. Then how the fuck am I gonna make any money?
4) There wasn't any statement on their website saying that once your referral switch plan, you are not going to get paid.

I demanded my share of the pay, and they replied:

1) since my referrals are not very active now, they decided to pay me only 10%!
2) on the referral switching plan issue, they are going to change the rules and they won't pay me.

Now, if this is not scam, what is?