There is no contradiction for Jer. 17.9 "The heart is more deceitful than all else and is desperately sick; who can understand it?" with "And ye shall seek me, and find [me], when ye shall search for me with all your heart" (29.13) except for Calvinism because only Calvinists teach Total depravity. The latter verse demands the former verse has nothing to do with Total depravity but is speaking of man's flesh.
The way Christians understand this is that man's flesh is utterly corruptible, can not be reformed, and must die, so the salvation of the cross effects that when He brings us to His sure death with Him in co-death. The old man dies.
So yes, the flesh is desperately sick yet we can seek Him if we are willing to search Him with all our heart and soul. This is true in spite of our wicked flesh because God has provided sufficient grace to all men. This is quite unlike your evil god you worship that has to irresistibly impose salvation on people and is so sick that he sends people to Hell without any opportunity to be saved. What love is that? If it is evil for us to behave that way then it is evil for your god and you. Why by wicked like your god? unless you want to.
If you want to be saved you will have to let go of the evil spirit you still worship that you allege makes you unable to repent and believe in Christ to be regenerated. A god who doesn't provide sufficient grace to all to be able to respond is not a good God but an evil one. Just as those who do go to Hell don't go because they were denied the grace, you weren't saved because you were given grace they weren't. You need to repent and believe in the Christ who is the Savior of all men, or you will go to Hell. Let go of your self and give it up for the One True God. Place your trust in this God not the one you purport.
"If you confess with your mouth Jesus as Lord, and believe in your heart that God raised Him from the dead, you will be saved, for with the heart a person, believes, resulting in righteousness, and with the mouth he confesses, resulting in salvation" (Rom. 10.9). Notice this verse lets you know everyone can do this, so preterition is false. Your god is a liar like the father of lies claiming God doesn't provide sufficient grace for all to be able to respond.
As I told James White today he's a bad guy because he prefers to self-exalt himself pridefully by claiming he was irresistibly selected, not one of the preteritioned. Why isn't he one of the preteritioned then since it was not his choice? for he had no choice in the matter according to his theory. He prefers to just assume this by his own power and strength rather than truly repenting and believing in Christ to be regenerated. Very sad really! He makes a mockery of the Church. Dave Hunt's book What Love is This? has a subtitle that says Calvinism's Misrepresentation of the Word of God. We can forgive Dave Hunt for not believing in partial rapture (he'll be judged for that), for no man is perfect; but they say his book will stand the test of time as the foremost work on the subject for at least the rest of this century.
May these words help lead you to Christ.