AMC131M01: Issue with DCDC Output When Controlled via SPI

The CLKIN frequency is 4MHz. I am attaching schematic for your reference.  

 AMC131M03_WriteRead(0x04, 0x31,AMCDataTx, AMCData);

if(counter < 1)
{
AMC131M03_WriteRead(0x03, 0x31,AMCDataTx, AMCData);
AMCDataTx[0] = 0x01;
AMCDataTx[1] = 0x0D;
AMCDataTx[2] = 0x00;
AMC131M03_WriteRead(0x01, 0x03,AMCDataTx, AMCData);
HAL_Delay(1);
AMCDataTx[0] = 0x0A;
AMCDataTx[1] = 0x00;
AMCDataTx[2] = 0x00;
AMC131M03_WriteRead(0x01, 0x31,AMCDataTx, AMCData);
HAL_Delay(1);
AMCDataTx[0] = 0x0A;
AMCDataTx[1] = 0x01;
AMCDataTx[2] = 0x00;
AMC131M03_WriteRead(0x01, 0x31,AMCDataTx, AMCData);
HAL_Delay(1);
counter++;
if(counter == 1)
HAL_GPIO_WritePin(GPIOB, GPIO_PIN_8, GPIO_PIN_SET);
HAL_Delay(1);

}
else

uint8_t AMC131M03_WriteRead(uint8_t command, uint8_t reg,uint8_t *txData, uint8_t *rxData) {
uint8_t txFrame[9] = {0}; // 10 16-bit chunks = 5 words of 24 bits
uint8_t rxFrame[9] = {0}; // Same size for receiving response

// Prepare the command word
uint16_t cmdWord = 0;

if (command == 1) { // Write command
cmdWord = (0x6000) | ((reg & 0x3F) << 7);
} else if (command == 0) { // Read command
cmdWord = (0xA000) | ((reg & 0x3F) << 7);
} else if (command == 3) { // Read command
cmdWord = 0x0000 ;
}
else if (command == 4) { // Read command
cmdWord = 0x11 ;
}else {
return 1; // Invalid command
}

// Fill the transmit frame
txFrame[0] = (cmdWord >> 8) & 0xFF; // Command high byte
txFrame[1] = cmdWord & 0xFF; // Command low byte

if(command == 1)
{
for(int i =0; i < 3; i++)
{
txFrame[i + 3] = txData[i];
}
}
// // Construct the input frame (DIN in 16-bit chunks)
// txFrame[0] = 0xB8;//((command << 8) | reg); // Command (8 bits) + Register (8 bits)
// txFrame[1] = 0x80; // Padding or CRC (if CRC is disabled)
// txFrame[2] = 0x0000; // Zero for 2nd word (high 16 bits)
// txFrame[3] = 0x0000; // Zero for 2nd word (low 8 bits padded)
// txFrame[4] = 0x0000; // Zero for 3rd word (high 16 bits)
// txFrame[5] = 0x0000; // Zero for 3rd word (low 8 bits padded)
// txFrame[6] = 0x0000; // Zero for 4th word (high 16 bits)
// txFrame[7] = 0x0000; // Zero for 4th word (low 8 bits padded)
// txFrame[8] = 0x0000; // Zero for 5th word (high 16 bits)
// txFrame[9] = 0x0000; // Zero for 5th word (low 8 bits padded)

// Transaction 1: Send command frame, ignore response
AMC131M01_CS_LOW();
HAL_SPI_Transmit(&hspi3, (uint8_t *)txFrame, 9, HAL_MAX_DELAY);
AMC131M01_CS_HIGH();

// Wait for response readiness (device-dependent delay, adjust as needed)
// HAL_Delay(1); // 1 ms delay as an example; adjust per device timing

// Transaction 2: Send dummy frame and receive response
uint16_t dummyFrame[9] = {0}; // Dummy frame to clock out response
AMC131M01_CS_LOW();
HAL_SPI_TransmitReceive(&hspi3, (uint8_t *)txFrame, (uint8_t *)rxFrame, 9, HAL_MAX_DELAY);
AMC131M01_CS_HIGH();

// Reconstruct the response frame into 5 words of 24 bits each
for (int i = 0; i < 5; i++) {
rxData[i] = rxFrame[i];
}

return 0; // Success
}

I am setting commands to set the frequency. I am sending these commands. 

Thank You for your response.
After changing the frequency also the issue is not resolved. I think there is some issue between communication as the response which I am observing is not as expected. I will explain the code which was posted above with the SPI settings and digital response which I got so it will be easy to trace the problem. I am including response of just 24 bits as that is my word size the response is stable so the SPI initialization seems correct I think the problem is with frames which are being sent.

The SPI is running at 781.25KHz as MSB first. The settings of clock are polarity low and phase 2nd Edge. 
The command sequence is ass follows:

After power up:

1. Read Status Register.

Command = 0x000000000000000000  Response = 0x048000

2. CLOCK Register all PWR = low power everything else default 

Command = 0x618000010D00000000 Response = 0x410600

3. DCDC_CTRL Register DCDC_FREQ = = 1.95 MHz to 2.12 MHz

Command = 0x788000080000000000 Response = 0x59FC00

4. DCDC_CTRL Register DCDC_EN = Enable

Command = 0x788000080100000000 Response = 0x59FC00

5. Read Status Register.

Command = 0x000000000000000000  Response = 0x004000

I don't know why but after these commands no matter what command I send the response remains same as 0x004000