Just buy a new slave module and replace the old one.
Don´t forget to reprogram the new one with the address of the old one. All new modules are supplied with address 0.
If you don't have an ASI programmer, just ask the supplier to program it for you.
Most of the ASI Masters have the capability of re-addressing Slave 0(the spare slave) to the address number of the defected slave, please check the Master manual & see if it can re-address your new slave.