It wasn't/isn’t my fault. It was/is the thief's fault.

[kadioguy]

[My conversation]

Kim: You borrowed my phone, so you should have to replace it.

Silver: I disagree. I didn't break the phone or lose it. It was stolen at home. It wasn't/isn’t my fault. It was/is the thief's fault.
----

a. It wasn't my fault.

b. It isn’t my fault

c. It was the thief's fault.

d. It is the thief's fault.

Which would you choose to use in this case? Are either of (a) or (b), and either of (c) or (d) all OK?

 

[jutfrank]

Since you seem to be in the middle of a heated exchange where Kim is blaming you, I think it's better to use the present tense.

It's not my fault!