How do i solve this and debug this because i already match it

.cpp(27): error C2181: illegal else without matching if cpp(37): error C2181: illegal else without matching if

hello,how to solve this problem I want to build a program about discount and total cost of order

below is the code.. it say the problem but i cant correct it thank you

 #include < iostream >
using namespace std;
#define retailPrice 20

int main()
{
float quantity,discount;
float totalCost;

cout << "Welcome to GLAMOUR bookstore,Enjoy our cool promotion.\n";
cout << "Please enter the quantity of packages you have purchased:";
cin >> quantity;
{
if (quantity<0)
    cout << "Sorry,quantity cannot be negative\n";

else if (0<=quantity && quantity<10) 
    discount = '0';
    totalCost = quantity * retailPrice;
}

{
if   (10<=quantity && quantity<=19)
    discount = '20';
    totalCost = quantity * retailPrice*0.8f;

else if  (20<=quantity && quantity<=49)
    discount = '30';
    totalCost = quantity * retailPrice*0.7f;
}

{ 
if (50<=quantity && quantity<=99)
    discount = '40';
    totalCost = quantity * retailPrice*0.6f;

else if (quantity>=100)
    discount = '50';
totalCost = quantity * retailPrice*0.5f;
}




    cout << "Total cost of purchase = RM" << totalCost << ".\n";
    cout << "discount =" << discount << "%\n";







   return 0;
   }