1. Since the equipment never arrived so much for using it properly.
2. Since the equipment never arrived so much for proper usage.
3. As the letter in question was never received by this office so much for its delivery to the next prospective recipient.
4. As the letter in question was never received by this office so much for its delivery.
@Gustavo, Co-Moderator posted:
They don't make sense.
Hi, Ahmad and Gustavo,
The sentences do make sense to me, but only when my mind supplies the comma that is absolutely essential and sorely missing before "so."
Ahmad is using "so much for" in its idiomatic, exclamatory sense (see here). Normally, "so much for" sentences are not introduced by a subordinate clause.
I'd prefer the sentences if each were divided into two separate sentences or into two independent clauses conjoined by a comma and then "so."
5. The equipment never (even) arrived. So much for using it properly!
6. The equipment never (even) arrived; so, so much for using it properly.
Ahmad, I assume you are already aware that idiomatic "so much for" clauses are only appropriate in informal, conversational English.