TOPIC: Is the sentence alright

Someone said" After the hampered by the rainstorm, even though we have finished the project one month late, the inspector issued the certificate DATE BACK/or DAY BACK to last month, so we can get our reward starting in April."
Is the sentence above alright?

The sentence contains a number of mistakes.
I would not use either "date back" or "day back", but use "pre-date" instead.
A model answer for the sentence would be:
"After being hampered by the rainstorm, even though we finished the project one month late, the inspector issued a predated certificate for 1 April, so that we can get our reward starting in I hope this helps.