Imaam pausing in the middle of the khutbah to make an announcement

Q: During the Jumu'ah Khutbah (the second Khutbah) the Imaam stopped in the middle of the Khutbah and made an announcement saying "whilst the Khutbah is on we are not allowed to talk". 

1. What is the ruling, will this nullify the Khutbah or not? 

2. What is the ruling with regarding to stopping the Khutbah to make an announcement? 

3. Will the Jumu'ah have to be made Qadha of?

Selling items on online stores with different payment options

Q: On Amazon and other online stores, there's a type of installment payment that involves interest. The buyer takes out a loan from the bank to pay for the product in installments, and the store pays the seller upfront without any interest. The buyer pays the installment to the store, and the store pays the seller the full price of the product immediately. 

It's not possible to disable this payment option on these stores. 

Would it be legal to sell on these online stores?

Accepting the information of a kaafir in matters of halaal and haraam

Q: I have been in touch with nutrabay company in terms of their product being halaal or not, especially the rennet used in whey protein, is it deprived from halaal source. 

I received a reply via authentic email id of their site: 

"Thank you for sharing your detailed query regarding whey protein and the source of rennet. We truly appreciate your awareness and careful consideration. 

We would like to inform you that the raw materials used in our whey protein, including the rennet involved in the process, are halal certified. You can confidently choose either whey protein isolate or concentrate, as both meet the required standards." 

My question is, can I consume their products assuming it is halaal by their email confirmation alone? As they did approve my detailed query and affirmed that their products are halaal!