Sentence, correct ?

[ansarparakkott]

Payment is under process, I will let you know once the payment has been done.

Most probably, it will be ready by this week itself.

Please let know whether the above mentioned sentences is ok?

 

[MikeNewYork]

Payment is under process, I will let you know once the payment has been done.

Most probably, it will be ready by this week itself.

Please let know whether the above mentioned sentences is ok?

Payment is in process. I will let you know once the payment has been made.
Most probably, it will be ready by the end of this week.

Please let me know whether the above mentioned sentences are OK?