Ok so I was flying from Van Nuys to Long Beach, started as a normal flight. I was tuned in to Los Angeles centre and requested to switch to Long Beach tower as I was approaching long beach, I was told to stay on Los Angeles Centre frequency. Long Beach tower started asking me to switch to their frequency, so I asked to switch frequencies which I was denied again, mind you I was on right base for runway 25r. Long beach tower then asked me again to join their frequency again, I was almost on final for runway 25r at this point, but LA centre was not letting me switch for some reason. I eventually received a violation. Screenshots are down below. I just want to know who’s at fault here. I had screenshotted the atc conversations prior to the violation because I had a feeling that I was somehow going to get reported.