E visa

So I buy e visa online and print it out, at the entry border from Phenom Penh, they did not check my e visa and they wrote an expirary date in my passport for 15 days, now 6 days before my e visa is due to expire, I try and renew it in Hoi An and they take no notice of the e visa and tell me that they can only go off the date in my passport, even though the e visa is printed out for them to see with an expirary date.

They tell me that only Saigon and Hanoi can process e visa extensions.

I feel as though I have been scammed and I’m in a situation now where I am facing a fine of £250 which I cannot afford. I really don’t trust e visas.