Cipher riddle - Who am I?

Question

Decode this chaotic mix of letters and symbols:

XLEMFHIWOVNYRUDQCJPASGBTKZ !AEZF ,FQPVPRHH TMDD RG QVU OUHIVJH FDJMVR R WVKZ RS SEGLBIZHJMFTRXAVKNQPDWYCUO

Here is the computing version:

XLEMFHIWOVNYRUDQCJPASGBTKZ !AEZF ,FQPVPRHH TMDD RG QVU OUHIVJH FDJMVR R WVKZ RS SEGLBIZHJMFTRXAVKNQPDWYCUO

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Now you got the cipher: Who am I?

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EDIT:

Clues are more clear in this version.

Decode this chaotic mix of letters and symbols:

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XLEMFHIWOVNYRUDQCJPASGBTKZ !AEZF ,FQPVPRHH TMDD RG QVU OUHIVJH FDJMVR R WVKZ RS SEGLBIZHJMFTRXAVKNQPDWYCUO

Answer 1

The answer is:

The Beatles

The message is:

WE HAVE A YELLOW VEHICLE AND WE NEED SOMEBODY, HELP!

Solution:

As Tas and M Oehm noted there are two full permutations of the alphabet starting and ending the text. Using a chaocipher with the first transposition "XLEMFHIWOVNYRUDQCJPASGBTKZ" as the left disk alphabet and the second one "SEGLBIZHJMFTRXAVKNQPDWYCUO" as the right disk alphabet, the middle text becomes "!PLEH ,YDOBEMOS DEEN EW DNA ELCIHEV WOLLEY A EVAH EW". When this text is reversed we get the answer above. The Beatles wrote songs with chorus lyrics "We all live in a yellow submarine" and "Help, I need somebody".

Answer 2

_{Not a complete answer}

The cipher appears to be a

Vigenère cipher

because

The first 26 letters of the phrase are all the letters in the alphabet, so this is likely the alphabet used for the cipher:
XLEMFHIWOVNYRUDQCJPASGBTKZ

Although the question mentions letters and symbols, there are really only two symbols and since

The ones before the first symbol are the alphabet, it's likely the ones between the ! and , potentially represent something as well.

Other observations:

The most common letters in the text appear to be R and V, and there is a double H and double D. Because R stands alone and appears in words of two, it's likely it's A or I