Formal — to staff
Vending · Machine · Issue
You
すみません、この自動販売機にお金を入れたのですが、商品が出ずに、お釣りも出てきません。
すみません、このじどうはんばいきにおかねをいれたのですが、しょうひんがでずに、おつりもでてきません。
Excuse me, I put money into this vending machine, but the product didn't come out and I didn't get any change.
Romaji: Sumimasen, kono jidōhanbaiki ni okane o ireta no desu ga, shōhin ga dezu ni, otsuri mo dete kimasen. / Reply Romaji: Mōshiwake gozaimasen. Dochira no shōhin ka, o-ikura ireraremashita ka? Kakunin itashimasu.
Reply
申し訳ございません。どちらの商品か、おいくら入れられましたか？確認いたします。
もうしわけございません。どちらのしょうひんか、おいくらいれられましたか？かくにんいたします。
I apologize. Which product was it, and how much money did you put in? I will check.
Gesture & etiquette
Pointing at the specific vending machine, and perhaps showing the amount of money with fingers if helpful, or pointing to the slot where money/product should come out.
Do not hit or kick the vending machine. Do not try to force it open. Seek staff assistance calmly.