[Grammar] Regarding the usage of "couldn't" in past tense

[Joe333]

Sentence: "Sorry I couldn't come/came back to you I was busy"


My question/doubt: Can couldn't be used to denote the past tense ? Is the above sentence right in using it ?


Thanks

 

[bhaisahab]

Sentence: "Sorry I couldn't come/came back to you I was busy"


My question/doubt: Can couldn't be used to denote the past tense ? Is the above sentence right in using it ?


Thanks

It's fine with "come".