=================================================================================
setwd("D:/MODIS_Download_R")
source('ModisDownload.R')
library(raster)
library(RCurl)
modisProducts()
x="MOD13A3"
ModisDownload(x=x,h=c(25,26),v=c(06,06),dates=c('2013.01.01','2013.12.31'))

==================================================================================

Error in .modisHTTP(x, v = version) :
the http address does not exist! Version may be incorrect OR Server is down!

==================================================================================

devtools::install_github('babaknaimi/rts')  # must install the latest one
library(rts)

setNASAauth("yourNASAlogin", "yourNASApassword", update = T) # authenticates at NASA's server
> username and password are successfully updated...!

ModisDownload(x='MOD13A3',h=c(25,26),v=c(06,06),dates=c('2013.01.01','2013.12.31'), mosaic=F, proj=F)