价格早就确认好了,所以涨价的部分不应该由我来付,英文怎么说

The price has been confirmed earlier(for a while),so the part of rising should not be our duty.

The price has been confirmed earlier(for a while),so we shouldn't take responsibility for the part of rising.

The price has been confirmed earlier(for a while),so there is no need for us to take responsibility for the part of rising.
希望有一个适合你！

The price has been settled before, so I'm not supposed to pay for the increased portion of it.

the price has already been set up,so i shouldn't have to pay for the appreciation part

the price has been confirmed already so that the price rising should be a burden of me

the price was proved before ,so the increasing price isn't payed for me now

The price has been fixed after the negotiation, therefore, I should not pay for any price increment.