how do we use ‘to omoimasu’

The informal forms are as follow:
to omou = to omoimasu (present tense)
to omotta = to omoimashita (past tense)

----- 'I thought you didn't want me to reply' -----

Henji wo shinakute ii to omoimashita kedo.
(I thought that it's alright if I don't reply.)

OR

Henji wo shinakute ii to ittan ja nai desu ka?
(I though you said that it's alright if I don't reply, isn't it?)


----- 'I thought you didn't want me to come' -----

Kite hoshikunakatta to omoimashita kedo.
(I thought you didn't want me to come.)


*Note: The 'kedo' is to tone down the statement.

Eg:
"I thought that it's alright if I don't reply, perhaps I was wrong."

-----'don't you think so?
'そう思いませんか?
(Sou omoimasen ka?)
そう思いませんか?
(Sou omoimasen ka?)

cc might say that it's:
そうだと思いませんか?
(Sou da to omoimasenka) by AZ
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Looks like you found an answer to say, 'don't you think so'.
Except your last comment. You don't seem to understand the difference except to get on your usual ping pong match.
What I was showing as examples on my post fit what I said in my previous post but you were twisting it around as you are doing here. Although I understand what you were tryiong to say when you mentioned 'sou omou' but you didn't seem to know how or when to use it at that time.
In this instance you obviously don't say
そうだと思いませんか？ for 'don't you think so?'. Anyone who knows Japanese language would agree with me on that.

You can say
君 そうだと思う？
そう(だと)思いますか？
そう思いますか？
そうと思う？
そうと思ってるの？

if you want to say "do you think so?" in sense of 'do you think it is so?' or 'Do you think it's true?'

how about the term for 'i don't think so'?
thanks

To cc:
It seems that I've offended you in a way or another. If so, I sincerely apologize for that. Perhaps I should work on my phrasing of words.

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To fusion:
"I don't think so" would be:

そう思いません。
(Sou omoimasen.)

OR

そうだと思いません。
(Sou da to omoimasen)

i was just wondering, how do you say i would like to buy (something) for (someone) using 'to omoimasu' at the end of the sentence?
Thanks