ばかりに: regretting the one cause of an unwelcome result
Focus on one cause while regretting a bad outcome. Distinguish this from temporal たばかり and identify the speaker's evaluation of the cause.
Singling out a cause
住所を間違えたばかりに、荷物が届きませんでした。 says that the package failed to arrive because the address was wrong. It conveys regret over a mistake or single cause leading to a bad outcome.
The speaker gives that cause particular prominence. This is not an investigation proving that reality involved exactly one cause, so distinguish causal emphasis from complete proof of causation.
Connections and comparison with せいで
Verbs connect in plain forms, such as 知らなかったばかりに. ルールを知らなかったばかりに、申し込みをやり直しました。 means that not knowing the rules led the speaker to redo the application.
住所を間違えたせいで can also identify the cause of an unwelcome result. ばかりに highlights regret that this one thing led to the outcome; for a welcome result, choose a suitable expression such as おかげで.
Different from having just done something
引っ越したばかりです。 temporally describes having moved recently. Check whether に connects a cause or whether ばかりだ describes a recent event.
安いという理由だけで選んだばかりに、すぐ買い直すことになりました。 says that choosing solely because it was cheap led to having to buy a replacement soon. The focus is regret about the causal choice, not how recently the choice was made.
Quick check: Does 一駅乗り過ごしたばかりに、遅刻しました。 merely mean that someone has just missed their stop by one station?
Show the answer and why
No. It says that going one station too far caused them to be late. ばかりに connects the regretted cause here rather than marking recency.