This paper presents the speech restoration and enhancement system created by the 1024K team for the ICASSP 2024 Speech Signal Improvement (SSI)  Challenge. Our system consists of a generative adversarial network (GAN)  in complex-domain for speech restoration and a fine-grained multi-band fusion module for speech enhancement. In the blind test set of SSI, the proposed system achieves an overall mean opinion score (MOS)  of 3.49 based on ITU-T P.804 and a Word Accuracy Rate (WAcc)  of 0.78 for the real-time track, as well as an overall P.804 MOS of 3.43 and a WAcc of 0.78 for the non-real-time track, rankingin both tracks.