epistolophobia
An abnormal or irrational fear of correspondence, especially the receiving or writing of letters or messages.
uncountable
One of the signs of Saussure's progressing reticence was what he himself called his epistolophobia or graphophobia. His letters to colleagues almost invariably began with apologies for a delay (sometimes of years) in responding.
Where it comes from
From Ancient Greek ἐπιστολή (epistolḗ, “message, letter”) + φόβος (phóbos, “fear”) + -ia.
Adapted from the Wiktionary entry epistolophobia (CC BY-SA 4.0).