"Bell patented his device on March 7, 1876, and the device quickly began to spread. By 1877, construction of the first regular telephone line from Boston to Somerville, Massachusetts, had been completed. By the end of 1880, there were 47,900 telephones in the United States."
I'm not sure what "giving me a call" means to you KF89 or anyone reading those words. However, I think in terms of English language usage in 1835 America it would not be the words one would use to describe a way in which someone should contact you about anything. I'm highly suspicious as to the reality of the supposed reprint poster? offering to buy slaves.
After all "giving me a call" sounds much more apt to be words spoken by someone experienced in the use of a telephone and making a telephone call. I am challenged to find any reference to its earliest usage so I can't confirm but i would say the poster is some kind of fakery what with the word usage being unlikely and telephones not being that common until 1880.