Issuing three talaaqs in the absence of one's wife

Q: I constantly have waswasa regarding different things, such as fears of losing important things and intrusive thoughts about divorce. 

Recently, while driving alone, I had thoughts of talaq, and I became worried about accidentally uttering the word and losing my wife. To counter these thoughts, I ended up saying the statement three times "main tumhy talaq deta hon" with my wife's name, thinking it would stop my mind from repeating it in front of her. 

However, I later read that divorce in isolation might still be valid. I also consulted an Imam at the Masjid, who assured me that the talaq is not valid. I would appreciate your opinion on this matter.

Businessman preventing two people from transacting a sale on his property

Q: Could mufti advise on the following: 

Person A owns a Cash n Carry, person B and person C both are his customer's and purchase from him. At the premises of person A, person B and C meet and start transacting on person A's premises. Person A in turns tells Person B that person C is my customer and you cannot supply him. 

1. Is this type of clause permissable in shariah where person A stops person B from supplying person C as he feels it's his customer. 

2. If person B and C transacted on person A's property, is the sale valid.