我父母去年９月来美探亲，B２签证今年３月初过期。我今年２月帮他们申请B２延期，后来由于疫情，到７月底才打了指纹, 然后我父母于８月底回国了。大概１１月多的时候又收到信，又让我父亲１２月１０号去打指纹，我当时还觉得奇怪，心想早就打过指纹了，而且人都回国了，就没管它。结果今天又收到信，说我父亲的延期申请被拒绝了，理由是７月底那次打的指纹不合格，让他１２月１０号再去打指纹，他没去。还说记录显示他８月底已经离境。说＂you failed to appear for the scheduled biometric services appointment. Additionally, there is no evidence in the record to indicate that, prior to the appointment time, USCIS received a change of address or rescheduling request justifying your failure to appear. Therefore, your application is considered abandoned and USCIS denies your request＂。 请问，我该怎么办？
另外，我母亲的延期前几天批准了。他们同时７月底打指纹，结果我母亲指纹合格，我父亲的指纹不"satisfactory", 造成后面这一系列后果。