Understanding of below sentence [closed]

I’m writing an email but I wonder whether the below sentence is clear to understand. If it isn’t understandable show me up the correction.

That the orders have been delayed we have decided to happen the cancellation of our orders.

It is not very clear what you are trying to convey with this sentence, but it seems that what you want to say is that you are cancelling your orders because they have been delayed. Here are a few options to convey that with more clarity:

Because of the delays experienced with our orders we have decided to cancel them.

or

We have decided to cancel our orders due to the fact that they have been delayed.

or

Given the delay we have decided to cancel our orders.