Buyer refuses to pay for extras works. (I didn’t create extras initially)

[ayalbaddage]

Buyer request Extra works. Before the start work. I clearly mentioned about the charges. But I didn’t create extras before start the additional task. (He is a fiver select buyer). After done the work i request to create invoice but he mentioned he misunderstood about the charges. (Already send the additional task).And he is not accept the invoice. 
What should i do now. 

[shahriyarmamun]

9 hours ago, ayalbaddage said:

Buyer request Extra works. Before the start work. I clearly mentioned about the charges. But I didn’t create extras before start the additional task. (He is a fiver select buyer). After done the work i request to create invoice but he mentioned he misunderstood about the charges. (Already send the additional task).And he is not accept the invoice. 
What should i do now. 

If you are a new seller. You must compromise for now. 

[mariashtelle1]

11 hours ago, ayalbaddage said:

Buyer request Extra works. Before the start work. I clearly mentioned about the charges. But I didn’t create extras before start the additional task.

Then if your client asked for something BEFORE you had an order, why didn’t you include in the price of the order? 
Explaining is not enough, if your client asked especially before order you had to include it in the price when you created the order