Problem in English Grammar?

To Sally:-
---(whether collapsed in 2007 doesn't matter.in your meaning of the sentence.)
---(We use "since" when we refer to a point of time in the past.)
---Error and correction:-
---We have visited City A since we were in yr. 2003.
---If you have contacted Tom in 2003, he may have collapsed in 2010 Okay !
---Whether his case collapsed in 2016 doesn't matter in your meaning of the sentence !-----
----If you want to add 2007 City A collapsed, or case 2016 your asking time, which shows the completed actions after a stated time 2003 in the past, then add another sentence.

你好😶
小弟認為應該要用Past Perfect tense

上述句子涉及兩個動作，一是「我去了city A」，二是「city A消失了」。
我去了city A ，要用過去完成時態；city A消失了在後，要用
一般過去時態

Past Perfect tense的主要表示過去某一時間之前已經完成的動作或狀態
使用這種時態，多會涉及兩個動作或狀態。一個在前，一個在後。
敘述前面的動作或狀態，動詞要用過去完成時態；敘述後面的動作
或狀態，動詞要用一般過去時態。
基於事情在過去發生，可以past perfect tense表示先後次序

Past Perfect Tense
動詞的過去完成時態的形態是：had + 動詞的過去分詞

以下是past perfect tense 的例子
用英文表示「我看電視之前已完成功課」，可以有多種方式.
1.When I had finished my homework, I watched television.
2. I had finished my homework when I watched television.
3. I had finished my homework before I watched television.

希望能幫助兄台😶😶。加油。

其實只要你把你要講的內容全部寫出來，你便自然會知道無論CityA現在是否"存在"，正確的講/寫法是：

I visited City A in 2003.

假如要加埋交代2007這CityA已不"存在"，則要加上另一句。

單單用動詞"visit"無論用如何改動時態都沒有辦法全部表達的。

I have visited City A. 的意思反而是表示你剛才去過CityA而現在(現在完成)告訴你我剛從那裏回來，即暗示City A是仍存在的。所以跟你"期望"表達卻"不說出來"的背景剛好相反。

I have visited City A. 或者是 I visited City A. 這兩種講法都可以，只是前者的現在完成式表達法會強調已經完成所做的事情，後者的過去式表達法就單純是表述曾做過某件事情。主要視你想要傳達的重點而定。

It is OK, but does it say exactly what you want to say?

語言的重點不是在於是否合乎文法!而在於"是否忠肯地表達你所要說的意思?"