SSI Payments or Supplemental Security Income payments are amounts established by federal law. There are rules governing who is eligible to collect SSI and the first requirement is based on age. Cost of living increases are tied to the inflation rate. By law, a person's social security benefit cannot be reduced. But there are several reasons why individual SSI recipients may see a decrease in the payments they receive. For example, if a person receiving SSI earns over a certain amount of income through employment or other means, and is collecting social security, the Social Security Administration can decrease SSI payments. Anyone on social security has the right to appeal benefit decisions and also has the right to representation by an attorney.