I am in Ohio - I have been dealing with a HML broker (my first mistake), he was referred to me by a fellow investor. I have been working with him for close to 3 months (in that time I have extended my current HML loan twice at $1,000 each time). With each new "deal", he calls on the phone with "terms" most often not in writing and not what I am looking for. I have paid for two appraisals and several app fees with nothing to show for it. At this point I am beyond done with this individual. I am out $4k in appraisals, fees & extensions. Now HML broker has sent me an invoice for $3,500 demanding I pay it immediately because he fulfilled his contract obligation to me. I never signed a contract and I don't have a closed loan. Is this person for real? Am I missing something?

You say:

in that time I have extended my current HML loan twice at $1,000 each time

And

I don't have a closed loan.

I don't understand.  How can you extend a loan you don't have?  I understand paying for an appraisal before closing the purchase.  That's pretty typical.  Application fees are more dubious.  Underwriting loans that don't close is part of the business.  Big up front fees are often a sign of a scam.  

@Jennifer L. Harrell I complete agree with @Jon Holdman - besides the appraisal fee, there should be no upfront fees.  If you don't have a contract with this broker, I don't understand why you would owe this person anything.  Typically brokers/lenders, etc. get paid when a deal closes and they take the risk (in terms of time investment in underwriting) that it might fall through.

I currently have a loan with my previous HML. I have to pay $1,000 to extend the loan until I can get my cash out refi done. I have been working with this person since early Feb. The note was due with previous HML in April. The new HML wants to charge me $3,500 even though he has not put the deal together & closed.

We don’t know what if agreement you signed with the new broker, unlikely a fee due for no closed deal would be enforceable anyway, but “pound sand” comes to mind, then move on.
Is the guy even properly licensed?

He certainly gives brokers a bad name.  Feel free to share his name so we can know who to avoid.

It doesn't sound like you're obligated to pay anything (since you didn't sign any contract).  If anything, he should be paying you for wasting your time and all the fees you incurred...