I'm afraid I've lost my wallet.
"I'm afraid" at the beginning of a sentence is used to introduce bad news.
Other examples:
I'm afraid I can't come to class today. I'm not feeling very well
I'm afraid I'll have to cancel our meeting.
I'm afraid I've lost my wallet.
Imamura uses have+past participle instead of the past simple form of the verb here because he is talking about something which happened recently.
Other examples are:
I've finished my report!
I've had too much to drink tonight.
I'm afraid I've lost my wallet.
This is a small, pocket-sized folder used to carry money, credit cards, ID, etc. The word wallet is used to describe this object when carried by a man. In the case of a woman, we use the word purse.
"Could you" + infinitive is used in this expression to make a polite request. You can use "can you" in the same way, but "could you" is more polite. In this case, the clerk is asking Imamura about the appearance of the wallet.
Other examples are:
Could you repeat that, please?
Could you send
me the information by e-mail?
This is asking about the material of an object.
Another example is:
This table is made of oak wood. It's an antique.
NB : don't confuse "made of" with "made by"! "Made by" is used to talk about the person or company that made the object.
For example:
This table is made of oak wood. It's an antique. It was made by a famous British carpenter.
"Can you" + infinitive is used in this expression to make a polite request. You can use "could you" in the same way, which is more polite than "can you" .
Other examples are:
Can you ask him to call me, please?
Can you send
me the information by e-mail?
...no wallets have been handed in...
The clerk uses have+passive ("be"+past participle) instead of the past simple form of the verb here because he is talking a recent past event. The passive form of the verb is used in this sentence because the action is the most important information, not the subject.
The phrasal verb (to) hand in, means to submit.
Other examples are:
Have you handed in your report to the boss yet?
I'm very lucky! Someone has handed my passport in to the police.
...no wallets have been handed in so far...
The clerk is saying that until now no wallets have been handed in, but there may be a chance that one could possibly be handed in later.
This phrase simply means, I'll contact you later about this.