【Nigerian cryptocurrency exchange Bitmama suspends virtual Mastercard service】Golden Finance reports that the Nigerian cryptocurrency trading platform Bitmama has temporarily halted its virtual Mastercard service due to unforeseen issues with its provider. Currently, African fintech companies are facing challenges with card services, including exchange rate fluctuations, chargeback fraud, and insufficient funds. Some fintech companies blame provider issues, while others mention high costs and limited revenue opportunities. Despite these obstacles, some fintech companies such as Bitmama and Chipper Cash continue to offer alternative card services.