My power steering stopped working and I took it to the garage. They said the motor is not working and found the issue was with the relays.

I got 2 relays form ebay and got it fixed to the motor.

After fixing the steering worked fine but only for a few hours. The following morning it was not working.

WHY is this. Where is the exacts issue. Is there a short in the motor.

yes this is good point
if brushes in motor worn out this could cause too much power to go through relays (micro)
i would do a scan of the power steering ecu though before replacing motor just in case it is ecu (power steering ) issue