Spanish to English Medical Medical (general) Appeal of denial of medical insurance benefits

This phrase came up in a written appeal of denial of medical insurance benefits. The writer is a Spanish-speaker living in Florida - no way to know the place of origin of the Spanish that this person speaks. The document is a printed form with hand-written entries from the member.
Here''s the sentence in which the phrase occurs: "Yo [NAME1 NAME2] espongo la razón que me llebaba [sic] a cometer este error". What follows expands on the details of the appeal, but does not add any useful information for the interpretation of this phrase.
I have searched with Bing & Google but haven't come up with anything very helpful. Most online resources just switch over to "esponjar", which I'm pretty sure is not relevant here.
I did see some traces of "espongar" in documents that appeared to be pretty ancient & mostly in Provençal/Occitan, about which I am essentially completely ignorant.
I think I have a basic sense of what the person is saying here, but I am curious as to whether "espongar" is perhaps a regional or local usage, but has fallen out of use in modern Castilian (if it ever was in use in Castilian).
Any help greatly appreciated.