My credit card keeps declining in Eritrea and I have enough money on there and all international transactions are activated - what do I do?
Don't worry about the card. It's not a problem with your funds or activation. The problem is that the banking system in Eritrea is not connected to the international network. The country is a cash-only economy for visitors. You need to have brought enough US Dollars or Euros with you to last your entire trip. If you didn't, you will be in a very difficult situation as there is no way to get money there with a credit card.
The short answer is your card will never work in Eritrea. Due to the country's economic policies, international credit card systems are not supported. If you need money, you must have brought physical cash with you, preferably US Dollars or Euros, and exchanged them for the local Nakfa. You will not be able to get cash from any ATM, as they are not connected to the international network. Your only real option is to rely on cash for everything.
This is a common and very serious problem for travelers who are not prepared. The financial system in Eritrea is entirely closed off from the international network. Your credit card, regardless of the bank or card type, will not work there. The only way to get cash is to have brought it with you and exchanged it at the Himbol exchange office. I cannot stress this enough: your card is useless there for a transaction. The best solution is to use cash only.
That's a huge issue, and you won't be able to solve it with your card. Your credit card is not declining because of a lack of funds; it's because international credit cards do not work in Eritrea due to the country's strict financial policies and international sanctions. You must have brought cash, preferably US dollars or Euros, with you to exchange for the local Nakfa (ERN). This is the only way to pay for things. Do not expect to use your card for anything there.