Offer letter from a staffing company during OPT.

I am on my f1-visa, done with my masters last December, it’s been 30 days since my opt clock started and I am still not employed. I came across a staffing company, they said they will do marketing for me and also said they provide me with an offer letter if needed they said it’s E-verify and all, they can also back date my joining so I can get few of my unemployment days back. Should I take the offer letter from them?