First, Make sure that the phone number that you registered when you activated your 2fa is the one you're currently using so try to remember it. When did you last logged in to your account anyway? to the point that you can't even remember it
After that you can narrow down the problem by using other services to send you codes like facebook, yahoomail etc. and if you received it without any problems then surely it's on cryptonator's side so obviously they're the only ones who can help you.
Regarding on their support, It seems they're experiencing some problems regarding gmail and some users also claims that it also involves yahoomail
As of now they haven't announced if they have fixed this but just from re-reading their old tweets, They do give update/s if the problem is fixed so I assume that the delivery problem is still ongoing.
This one is on their site. A lot of crypto related sites are also experiencing the same thing as a result their response time is getting slower and slower as the work to be done increases so the 2-3 days is just another unsustainable claims that every support team makes.
They have said inquiries on their social media accounts will be ignored so it's no use in trying but there is a guy here who's affiliated with them so try sending him a PM although his last active date was on Dec 8: teamcryptonator
It's not a scam but it's also not a good place to store your funds either.