Need help - New experience with prospective tenant . Doozy

[Steve S.]

without revealing too many specifics, here's a quick rundown of my situation.

I have a lease coming up and have been marketing hard.  I find a single mom of 1 that loves the place and submits an application.  All check out goos.  I tell her i need the deposit and signed lease.  I send her the lease and tell her to let me know when she can talk over the phone to go over it and make sure there's no questions.  She says great.

Day goes by.  No deposit. 

I text her and ask about deposit.  She apologizes profusely and says she will get it to me electronically tomorrow.

Day goes by.  No deposit.  I text she says, i'm very sorry, but my mom is going to mail you a check.  You'll have it in 2 days. 

Check arrives.  I cash it.  I ask again for the lease.  She says I'll get it to you tomorrow.

Day goes by and no lease.  She says, I will be in town in 3 days and would like to take some measurements at the place and will drop the lease off then.  I say ok.

3 days go by, she arrives and I ask her to text me when she leaves as tenant had left for a bit so they could take measurements for their stuff.  She texts me that she's leaving.  I ask how'd it go.  She said great.  I said where'd you leave the lease so I can have the tenant put it aside for me.

She says "oh my gosh.  I totally forgot.  Can i mail it to you and you'll have it friday"

Meanwhile i have another prospect praying she falls through so they can give me deposit and lease.  They call me asking if they signed the lease and if not, they will do it tonight.

Do i have any obligation here?  I will fully refund their deposit.  I need to tell this person who has been flaky for whatever reason that I'm going to different direction.  I'm sure they will be PISSED as they've spent time and think they have everything locked down but yet i have no lease, only a deposit.

What should i do here?  She's made me very nervous and it seems like she's somehow running a scam on me.