B2B Sales Letter Needed For Local Social Media Company

Hi Guys! I run a small social media company and I offer three services. Social Media Management (main service), Social Media Marketing (addon to management) and I also sell social media decals and stickers. I have created a sales pdf document (brochure) that I want to snail mail to local business's. I am in need of a very well done sales letter to get business's to want to sign on to our social media management packages and the idea is to sell them on the idea that they are hiring a social media manager/director at a fraction of the cost. In the sales letter they need to know the benefits to social media and why hiring us is best for them. I will send the pdf document that I have so you can go over it, it would be very beneficial for the writer to have ideas on social media and why it is important. If you could send me some samples etc.. that would be great. Please let me know if you have any questions. Thank you!