我这样翻译可以吗？谢谢！（请帮我看看有没有什么语法错误）

可以，可是可以更好，而且你后面那一句没翻出来。我再重新翻一遍吧。

We are glad to confirm that we have received this new direction in March. But we cannot utilize this formulation due to the fact that we don't have A3 (we've never received A3). At that time we have consulted Mr Li, and he directed us to continue production based on the old formulation.

Please inform us on what we should do now.

已经不错了， 我再重新翻一遍吧。 标准答案

We have already received in March of this new formula. However, because we do not have A3 (we have never received A), so we can not use this new formula.
At that time, we asked about the days, he let us in accordance with the old formula for production.
Will we now how to do.

can not最好写成cannot
Mr后面最好加".", 单独mr也有其它的意思(计算机方面的),不过没什么大碍.

We are glad to confirm that we have received the new formulation in March.
But we cannot use this prescription cause we have no A3(We have never received A3).
And we consulted Mr.Li at that time, he let us keep producing according to the original prescription.
Please inform us of what we should do now.(是不是inform后面,加on,of,about都是可以的?)