initializeMonnify calls the platforms APIs to initialise Monnify
arguments apiKey, contractCode, applicationMode are required for this
method to function.
It returns a String or null
makePayment sends request to the respective platforms to make payment
Arguments String amount, currencyCode, customerName, customerEmail,
paymentReference, paymentDescription, and paymentMethod are required
for the method to work seamlessly
customerPhoneNumber is the only param that is not required