Missed biometrics appointment

[akhan19]

Please could someone advise

Since yesterday,I have been worried sick

My wife has applied for ilr and yesterday, we received a letter stating she had to have her biometrics taken within 17 days of receiving the letter. That letter was dated 20th April and it is now 22 days since the letter was sent out but we only received it on the 11th may

It also stated we missed a original appointment. However, I did no recieve that letter at all

I am going to a post office with my wife today as they offer a walkin service to get it done ASAP but on the letter it says the application could be rejected as invalid if we don't do within 17 days of the date on the letter

I can't even ring ukba until Monday as they are not open over weekend

How bad is this situation and can I appeal if they reject the visa?