Hi
I used my Credit Card in an unmanned station in NZ without a problem. Check with your Credit Card company, as it may be a security issue with the CCC, rather than the filling stations. The CCC may not authorise transactions in unmanned stations in certain countries. This may be to avoid fraudulent losses i.e. stolen or skimmed cards, for which they don't have an agreement with the foreign company to recover/share any loss.
If this is the case, perhaps if you are a regular traveller to these countries and need this service, it may be worth switching to another CCC. Is there a forum for Long distance lorry drivers who may have encountered this problem and can suggest a solution?
Huckster