If both accounts were only just opened in April 2017 and then have been extensively complaining about every little thing, that does raise a red flag. Add to that the extensive point purchasing and I can see why Hilton feels like something is off about the OP and their spouse.

Newly opened accounts having "tens of complaint mail per month per the OP" with Hilton is indeed a red flag in my eyes. If I were the OP and so dissatisfied anyway with my stays, I wouldn't be purchasing points for that hotel chain. I also wouldn't give two hoots about Hilton closing my account, since the hotels were crap anyway to warrant a extensive list of complaints.