Should I Trust my New Botox Doctor?

I found a new Botox ophthamologist in a new country, but he wants $800 cash and I am new here and I have not met anyone who has had Botox from him. I loved my Botox doc in NYC. He always took my card, always said if I had any problem, I could come back...it only happened once. The result was obvious in a day or 2 and lasted 6+ months. I went for several years, beginning in my late 40's. I went to a cheap Botox place first and got no results at all. I went back and they gave me a lot of excuses, so I almost gave up. But then, I got very lucky. I paid twice as much when I went to an ophthalmologist and I've looked beautiful ever since. Until I moved to San Juan. Now I am afraid of this new Doc. He has diplomas all around the room, and he says he went to/graduated from the Mayo clinic. I haven't had it yet. I'm scheduled for tomorrow, but unless he guarantees in writing that he will redo it to my satisfaction free of charge, I don't think I should give him $800.00 cash. Is this normal? Should I trust my new doc?