When you install, K2Store sets USD as the default currency. When store owners change the currency code, they often forgot to update their default currency in their store profile.
When you see the currency symbol missing, it is an indication of the following
1. You have either changed the currency code or deleted the USD and then created a new currency for your country.
2. You forgot to reflect these changes in the Store profile.
Go to K2Store admin -> Set up - > Store Profiles
Open your Store Profile.
Choose your Default Currency.
So CLICK the SAVE button.
Still not seeing the Currency symbol, open your store profile again and click SAVE again.