User Accounts, submitted articles, and Issues got deleted

Dear All
I have been using OJS 3.2.0 since last 2 years. Small issues arise but were tackled. Recently I have faced a serious issue and I am unable to trace the reason for that.
Actually some of user accounts, submitted articles, and even published issues have been deleted automaticaly, I dont understand why so happened and I am unable to trace them all back.
There was an issue in the website some days back and I asked for support from my hosting provider, and all this happened after that issue was resolved by hosting provider support team.
Can any one help me out or can give me a clue what was the reason and how to recover all that stuff.