Are both receivers registered to the same account?
I have seen a similar problem, whereby a customer was using two receivers; one was registered to Customer A, the 2nd receiver was registered to Customer B.
The customer (in a 3rd location) was sharing two different people's accounts (one receiver from each).
Customer A had a service call, and a Shaw Tech installed the new XKu LNB on their house. This knocked out service to the receiver registered with Customer A.
The 2nd receiver continued to function because Customer B's dish still had a Dual Sat LNB installed.