Confusion between samples per second and samples per symbol
A digital communications signal such as QAM can be generally written as $$s(t) = \sum_{n=0}^{N}a_n p(t-nT),$$ where $a_n$ are (possibly complex) amplitudes taken from a finite alphabet, and the symbol rate is $1/T$. The pulses $p(t-nT)$ are often called "symbols". Matlab commands that ask you to specify "samples per symbol" are asking how many samples you want to use to define $p(t)$.

Of course, since you know the pulse duration, specifying the samples per symbol is an indirect way of specifying the sampling rate.