Here's a few verses I use to counter the claim of instant heaven at death:
2 Corinthians 5:8
This text says, "we are willing rather to be absent from the body, and present with the Lord."
This text in in no way suggests that immediately after death we go into the presence of the lord. Paul clearly taught that the dead remain unconcious until Christ returns from Heaven to resurrect them.
If we read 2 Cor. 5:1-9 with the understanding that "earthy house" means our mortal bodies, "house from heaven" means our glorified immortal bodies, "naked or unclothed" means dead or in the grave, then the entire passage represents Paul's intense longing to be in a glorified body with Christ in His soon coming kingdom.
This reconciles perfectly with Paul's other verses below. If we read the one avove to say we gain immortality at death-
then Paul is contradicting himself and teaching 2 resurrections, one at death, one at Christ's second coming:
1 Thessalonians 4:13-16
"But I would not have you to be ignorant, brethren, concerning them which are asleep, that ye sorrow not, even as others which have no hope.
For if we believe that Jesus died and rose again, even so them also which sleep in Jesus will God bring with him.
For this we say unto you by the word of the Lord, that we which are alive and remain unto the coming of the Lord shall not prevent them which are asleep.
For the Lord himself shall descend from heaven with a shout, with the voice of the archangel, and with the trump of God: and the dead in Christ shall rise first..
1 Corinthians 15:21-23
"For since by man came death, by man came also the resurrection of the dead.
For as in Adam all die, even so in Christ shall all be made alive.
But every man in his own order: Christ the firstfruits; afterward they that are Christ's at his coming."
1 Corinthians 15:50-55
Now this I say, brethren, that flesh and blood cannot inherit the kingdom of God; neither doth corruption inherit incorruption.
Behold, I shew you a mystery; We shall not all sleep, but we shall all be changed,In a moment, in the twinkling of an eye, at the last trump: for the trumpet shall sound, and the dead shall be raised incorruptible, and we shall be changed.
For this corruptible must put on incorruption, and this mortal must put on immortality.
So when this corruptible shall have put on incorruption, and this mortal shall have put on immortality, then shall be brought to pass the saying that is written, Death is swallowed up in victory. O death, where is thy sting? O grave, where is thy victory?