Quote - And as for the scripture at Jeremiah 29:10, every modern translation I looked at, except for ours, said that 70 years must be completed FOR Babylon, not at. - End quote
The WTS actually claims that the 70 years are FOR Babylon:
[Isaiah’s Prophecy 1 p. 253-254 par. 21 – He says: “These nations will have to serve the king of Babylon seventy years.” (Jeremiah 25:8-17, 22, 27) True, the island-city of Tyre is not subject to Babylon for a full 70 years, since the Babylonian Empire falls in 539 B.C.E. Evidently, the 70 years represents the period of Babylonia’s greatest domination—when the Babylonian royal dynasty boasts of having lifted its throne even above “the stars of God.” (Isaiah 14:13) Different nations come under that domination at different times. But at the end of 70 years, that domination will crumble.]
Quote - and get some help researching my next rebuttal. - End quote
This is all you should need to ask the WTS:
(Q) When did Jehovah say he was going to call Babylon to account?
[Jeremiah 25:12 “‘And it must occur that when
seventy years have been fulfilled I shall call to account against the king
of Babylon and against that nation,’ is the utterance of Jehovah,]
(Q) What year did Jehovah call Babylon to account?
[8-1-81 WT
p. 27-28 - “The idol-worshiping
Babylonians now were in line for God’s judgment to be executed upon them. That happened in 539 B.C.E. when Babylon was
overthrown by the Medes and the Persians.”]
Jehovah's appointed time to call Babylon to account was when 70 years had been fulfilled and being that he did so in 539 would mean the 539 must have been the 70th year of the 70 years, which would mean they began in 609. To claim that the 70 years were from 607 to 537 would make 539 the 68th year of those 70 years and it would mean that Jehovah jumped ahead of his own appointed time by 2 years, but according to the following that can't be the case, which means 607-537 is wrong and 609-539 is correct.
[11-15-98
WT p. 15-16 par.3 – We know that Jehovah is the Great Timekeeper, and we have
confidence that he never fails to fulfill his
purposes at his appointed time.]