The following is what I'd ask myself in order to prove that the circuit is capable of working. I would need an oscilloscope and a signal generator with variable frequency capability and sinewave output. If you haven't got these then maybe try simulating the circuit. If you haven't got a simulator then maybe someone has a better idea?
If you disconnect C3 from Q1 and connect a signal generator into C3, at what frequency does the waveform on the base of Q1 become 180º phase shifted to the waveform from the signal generator. Also if the signal generator in inputting 1Vp-p, what is the signal on the base when 180º phase shift takes place?
Is the 180º shifted frequency what you expect it to be?
Is the signal going into the base what you expect it to be?
Is the attenuation produced by the phase shift network less than your gain?
If any of the the above questions is a "NO" then you have to figure out why. That's what I'd do.