If you just want to demodulate, then it is not necessary to recover I and Q components. What you have is most likely the QAM symbols. For example, for $16$-QAM they are $16$ different integer values that are assigned to different constellation points. You need to know the type of assignment (i.e. coding) that is used in the QAM constellation at the modulator.
At the $16$-QAM modulator, every $\log_2 16=4$ data bits are mapped to a certain constellation point (which ultimately is identified by an integer). For instance, $0101$ can represent the symbol $5$, and so on. Gray coding is usually used for this purpose, but it is not always the case. So you need to find out the exact constellation mapping and then, the demodulation process is nothing more than the inverse of that mapping. So when there is a $5$ your data bits are $0101$.