Voltage and current inside a relay works in a slightly different way.
First of all, current will create heat inside the relay. Depending on the conductor size, you will likely have a maximum current that can pass through the relay without burning it up. In your case: 2A. Therefore, no matter what the voltage is, you will need to be bellow 2A on your load.
For the voltage, you need to picture how a relay is made inside your head. A metal piece is moving back and forth creating or cutting a contact between two port. That metal piece is controlled by a electric coil that clamp the contact on. When the contact is not clamped, there is a distance in between the contact and the metal piece. While air is a nice dielectric (insulator) there is a fixed voltage that it can withstand before it begins to be a conductor. Think of lightning, electric ark, welding. Therefore, if the voltage is above the rated voltage, you will most likely create an ark inside your relay and this is not a desirable thing at all.
In the case of a solid state relay (your case) the switching is done with a semiconductor. Therefore, the dielectric will be different and there won't be any moving parts inside it. But, exceeding the voltage may break down the device or cause it to ark in surprising ways.