It was quite a costly error.

Police in northern Wales gave a cell phone to a burglar they wanted to keep tabs on and ended up having to settle a $55,000 bill, officers revealed Monday in response to a freedom of information request filed by the Daily Post.

The unidentified man from Llangefni was out on bail when North Wales Police mistakenly gave him a phone containing a contracted rather than a pay-as-you-go SIM card.

After being convicted and jailed, the man reportedly gave the phone to two associates who allegedly used it to rack up an astonishing debt over just six months, the Post reported.

Cops spotted the soaring cost in early 2014 and arrested the associates on suspicion on theft, reports the BBC. But they were powerless to prosecute either them or the burglar after it emerged he’d never signed a contract to agree on how the cell phone could be utilized.

It left police having to foot the bill.

No police staff were disciplined following the blunder. North Wales Police said Monday that the department has since tightened up its policies on cell phone use.