Is this sentence correct?

[Zoe2008]

This is to remind that, please return all the customer's questionnaire no later than 25 March 2008. Thank you

 

[Offroad]

This is to remind that, please return all the customer's questionnaire no later than 25 March 2008. Thank you

my shot:

This is to memind you to return all the customer's questionnaires no later than 25 March 2008.

Please teachers, proofread these senteces.

many thanks