Welcome. I am very fond of the MXR-130 Receiver as you can tell by my signature line below. There are several of us here who use and work on them so you have come to the right place for help.
A member here "circuitsandconcepts" has an eBay store were he sells very good quality replacement relays. I believe he still gives free shipping to members here. Send him a PM or eBay message to find out.
Output Relays to repair CARVER MXR-130 -150 -900 -2000 THE RECEIVER