Upon collection, we noticed that they have only 11 pieces to be ready for collection, not 12 pieces as mentioned in your email.
The collection happened in the past, so you can't say ' say 'they have only . . ' Also, try to avoid repetition (.
New words, one handy idiom, and a 2-minute quiz — delivered to your inbox to keep your streak alive.
The collection happened in the past, so you can't say ' say 'they have only . . . '
Also, try to avoid repetition (. . . collection . . . collection. . . )
noticed is too casual here. I suggest found.
Say eg Upon collection, we found that they had only 11 pieces ready, not 12 as mentioned in your email.
Clive