-라고 무슨 말이에요 is not right.
There should be something functioning like a subject before 무슨. -라고 is an adverbial phrase.
(Also, it is spelled as 말이에요, not 말이예요)
Quoting a phrase or sentence to ask about it is not that simple if you consider all the different cases.
Here are the basics.
1. When you are asking about a word or a short phrase - direct quotation.
- 방학이 무슨 말이에요? = 방학이 뭐예요? = 방학은 뭐예요?: What does 방학 mean?
- '저 친구(는) 이제 끝났다'가 무슨 말이에요?: longer phrase - an indirect quote may sound more natural.
2. When asking about a longer phrase or a sentence.
A 저 친구 이제 끝났다는 게 무슨 말이에요?: What does 저 친구 이제 끝났다 mean?
A 저 친구 이제 끝났다는데 그게 무슨 말이에요?: What does it mean, 저 친구 이제 끝났다?
B 이제 그 친구는 끝이라는 게 무슨 말이에요?
B 이제 그 친구는 끝이라는데 그게 무슨 말이에요?
3. To ask whether they are talking about something you have in mind.
A 제 말이 틀렸단 말이에요? Do you mean I said it wrong? (-단 is short for -다는)
B (방학이) 휴가란 말이에요? Are you saying it (방학) is 휴가? (-란 is short for -라는)
You see -다는 (A) and -(이)라는(B) endings of the verbs.
-(이)라는 is only for the special (particle) verb 이다 in the present tense, while -다는 is for all other cases.
이다 attaches to nouns, like "is something" in English, which means -(이)라는 always follows a noun or pronoun.