Hi friend )
As for me, when I bought my contract at the end 2014 year, haven't ROI (((
My hashrate is  1TH/s (contract from 2014-12-21) and my payout (for ex.) :

0.01109828 - one of TWO weeks (2015-03-30)
0.01021753 - one of TWO weeks (2015-03-16)
0.0116527 - one of TWO weeks (2015-03-02)

...
but this service to review our ROI here -> http://www.cloudmining.website/calculator.php
for 1 Th/s it may be 0.010765 !!! BUT PER DAY !!!

At the end, we can calculate out ROI -> ~ 860 DAYS ((((

How can I motivate this service to fulfill its conditions, can write a petition, or simply watch as these guys are deceiving us?

Rather than fighting here take a small piece of advice from my end. Get a new contract @ their new rates. These are paying exceptionally well. I got this notion from a discussion at their forum and it has worked. This is how your old investments will get covered. Decision is yours. Over to you...