Would u check these sentences, teacher?

We will give a full refund. / We can give a refund but there is a 10% penalty. Just send your ID and coupon number to me by an e- mail. Then, I will make a change on your reservation. Just send your defective item to me by express. Then, I will replace the defective item. Why don’t you drop by our office? If you give your coupon number to me, I will issue new tickets right away. Why don’t you give some presents to customers? They will appreciate it so you can get more feedbacks from them. Why don’t you give some presents to employees such as towel? Everyone would admit it. Just call the customer service center. I guess they will take care of this problem. Just call (the reception desk / the marketing department / the general affair department) I guess they will take care of this problem effectively.

Hello there! ^^

I hope your having a good time today.

Here are my corrections.

It\'s just a few.

Because you made good sentences.

Anyway, if you still have questions or concerns, just tell me during our class. 

I\'ll see you tomorrow! ^^

T. Hannah^^

We will give a full refund. /

>> CORRECT

We can give a refund but there is a 10% penalty.

>> CORRECT

Just send your ID and coupon number to me by an e- mail.

>> Just send your ID and coupon number through an email. 

Then, I will make a change on your reservation.

>> CORRECT   

Just send your defective item to me by express.

>> CORRECT

Then, I will replace the defective item.

>> CORRECT

Why don’t you drop by our office?

>> CORRECT

If you give your coupon number to me, I will issue new tickets right away.

>> CORRECT

Why don’t you give some presents to customers?

>> CORRECT

They will appreciate it so you can get more feedbacks from them.

>> CORRECT

Why don’t you give some presents to employees such as towel?

>> CORRECT

Everyone would admit it. 

>> Everyone would like it.

>> OR: Everyone would appreciate it. 

Just call the customer service center.

>> CORRECT

I guess they will take care of this problem.

>> I am pretty sure that they will take care of your problem.  

 Just call (the reception desk / the marketing department / the general affair department)

>> Just call the following department concerned: the reception desk, the marketing department and the general affairs. 

I guess they will take care of this problem effectively.

>> They will take care of your problem immediately/ right ahead.