Please mark the correct answer so users can find them later on
I wonder if it could have been a neighbour of yours? Or is this just a complete coincidence?
There is nothing that needs to be done - just throw the SIM away if you don't want it.
Talk about egging him on, it's just the free sim card confirmation nothing els, all your doing is making panic when there is none
The OP also said "the same day I get a letter from a different company about another order I never made", which suggests a pattern of identity theft rather than a simple accident.