I need urgent help

I applied for spouse visa extension FLR(M) 5 year route.
Desicion is approved and visa is granted for 30 months. But they put me into 10 year route now saying I didn't met the english requirement as I didn't provided UK naric letter confirming that degree was taught in English.
I did provided the statement of comparability from naric which states that my degree is comparable to uk bachelors degree. My degree was taught in English hence I also provided proficiency in English certificate from my university. If you see english language guidance on uk visa website, it is not stated that we need to provide a letter as well.
Now they didn't gave me the right to appeal as they knew I could have provided the letter. What should I do now? I am really worried. It's not a big mistake on which they put me on 10 year route. My friends and relatives also applied like this and they got visa on 5 year route, then why me

PLEASE HELP