hadn't 和 didn't have的区别

didn't have 里面have 是动词，有实际意义，是“有”的意思;
hadn't 里面have 是助动词，无实际意思

I didn't have a credit card with that company. 我(那个时候)没有那家公司的信用卡。表示过去某一个时间,句子中的意思是过去某个时候没有信用卡，但是现在可能情况变了：有或者没有。

---Obviously, did/didn't是过去时，meaning并非现在就怎么怎么样。eg:Did you hear that? I didn't hear that. 你听到什么动静了么？没啊. What did you say? I said nothing. 你说啥？ 我（刚才）啥也没说阿。

I hadn't had any credit cards. 我(那个时候一直都)没有任何信用卡。表示过去一直持续的状态(因为是hadn't:用了过去完成时,表示现状也可能已经改变; 如果是haven't:现在完成时，就表示一直到现在都。。。)
eg:I hadn't heard that.我始终没听到啥啊。/我从没听到过啥啊。I hadn't said anything. 我那时候一直都没说话阿。/ 我从没说过啥啊。

前者Had是助动词的否定，一般用在完成时，没有实际的意思！后者Had是动词！意思是“有”，否定当然就是didn't have

hadn't是过去完成时
didn't have就是“没有”的过去时

一个是过去完成时一个是一般现在时