@Eric,
Just recollected same thing few days back with one of the customer, though i was called just for cleaning the infection but this is the same mail which caused it, i am pasting the header below and it has the same pattern infact it is originating from same network as seen in your header too, this mail contains a js script which on execution encrypts all the files, basically this is a ransomeware infection by the name nemucod and then you are left with paying something to decrypt all the files, but there is solution to this without any worry, if you are infected then and need support let me know.
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Subject: Problem with parcel shipping, ID:00000750279
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