After making payment, I get this error

[seanmavley]

That's what shows up after successful test payment.

Exception - set_exception_handler(): Argument #1 ($callback) must be a valid callback or null, function "enrol_paystack_charge_exception_handler" not found or invalid function name

[123AKAk]

Yes, I get the same issue.

Exception - set_exception_handler(): Argument #1 ($callback) must be a valid callback or null, function "enrol_paystack_charge_exception_handler" not found or invalid function name