Benedict Arnold next wrote a series of letters to Clinton, even before he might have expected a response to the 7 July letter. In a 11 July letter, he complained that the British did not appear to trust him, and threatened to break off negotiations unless progress was made. On 12 July, he wrote again, making explicit the offer to surrender West Point, although his price rose to £20,000 (in addition to indemnification for his losses), with a £1,000 down payment to be delivered with the response. These letters were delivered by Samuel Wallis, another Philadelphia businessman who spied for the British, rather than by Stansbury.