renege|reneged|reneging

他赌输了却想赖账。

He lost the bet but tried to ___renege on the payment.

他答应还钱却最终赖账了。

He promised to pay back but ___reneged on his debt.

他答应帮忙，却在最后一刻反悔了。

He promised to help but ended up ___reneging at the last minute.