Intro
Mirza Ghulam Ahmad was the classic punjabi fraudster.  He had promised the Muslims of the Indian sub-continent 300 arguments in favor of Islam in roughly 1878.  However, he only delivered one argument, and that argument was his claim of prophethood, which immediately got him declared as a Kafir by the ulema in India.

A summary of the quotation of Seeratul Mahdi- Number 123
It says that 300 arguments were Written on 2500 pages but in fact Only One Incomplete argument could be printed in Braheenay Ahmadia in total of 4 volumes . He says he heard that earlier writings were burned.

The scans

MGA made lots of excuses for the delay

MGA claims to write 300 arguments in support of Islam
“We wrote Braheen e Ahmadiyya after observing hundreds of defects and evils in the society. In the mentioned book, the truth of Islam was shinning in fact more than the sun because of 300 strong and sound arguments.” (Braheen e Ahmadiyya 2, Roohani Khazien 1, page 62)

MGA claims that he has instead written millions of arguments
“People said that the promise of giving arguments mentioned in Braheen is not fulfilled. Though there are millions of arguments in Braheen for the truth of Islam.”
(Badar,volume 6, No. 17, page 7-8, 25 April 1907) (Malfoozat volume 5 page 206, new edition)

MGA on the delay of the Braheen and other people’s investment money

In 1900, MGA and his team wrote: 

[RK, v 17, pp. 448-458; Arba`een Number 4]. The article is dated
December 1900. In this he censures his critics and claims that he has Divine support etc. Toward the end of the article is the following:

“””If I have received from you the payment for the price of Baraaheen-e-Ahmadiyya then I invoke the oath of God Almighty upon you, in Whose presence you will be made to appear, that [you should] return all those four parts of Baraaheen-e-Ahmadiyya to my custody and take your money back. Look, I make this open announcement that after this if you demand the price [refund] of Baraaheen-e-Ahmadiyya and, having shown [those parts] to some friend of mine, send [return] all four parts to me, as value payable, and if I, after receiving the four parts, do not pay their price, then [may] the curse of God [be] upon me. … And prior to this I have published three announcements, regarding the price [refund] of Baraaheen, which had the same content that I am prepared to return the price. [These people] should return all the four parts of my book and receive from me the few paltry coins that they are dying for. … [Dated] December 15, 1900 AD [RK, v 17, pp. 457-458; starts at last line of p. 457, above the marginal note; Arba`een Number 4].”””

In 1900, MGA promised 40 parts for his books Arbaeen, however, he only gives 4 calls it even
“Just as God had initially fixed 50 prayers then reduced it to 5 in place of 50, similarly according to the Sunnah of Rabb-e-Kareem, I reduce for the sake of viewers and pronounce number 4 as 40.” (Roohani Khazain vol.17, Arba’een No. 4, Page 442, http://www.alislam.org/ur…uhani-Khazain-Vol-17.pdf, PDF 477)