Help! Simple C Program Help!

Yes you hardcore programmers may laugh but I can't get this working?!?!?
I know its my functions!!

I'm just wondering if anybody can see anything right away if they are that good at it. Obviously I am not. Thank you in advance!

Sincerely, Frustrated and obviously new

Code:

/*
  Program Internet Service.
  
  Add your own documentation.

*/

#include <stdio.h>
#include <stdlib.h>



/* Global Variables */
int cust_num, hours, month_charge, total_cust;
char serv_code;
float  average, total_charge;




/* Function Prototypes */
void intialize_2100(void);
void obtain_input_2200(void);
void process_customer_2300(void);
void display_details_2400(void);
void calc_average_2500(void);
void display_summary_2600(void);
void calc_monthly_charge_3310(void);
void update_accum_count_3320(void);
void calc_bus_charge_4110(void);
void calc_econ_charge_4120(void);
void calc_unlim_charge_4130(void);
void update_accum_4210(void);
void update_counter_4220(void);



/* Program Mainline */
int main ()
{
    initialize_2100();
    obtain_input_2200();
    while (cust_num !=  999)
   {
        process_customer_2300();
        display_details_2400();
        obtain_input_2200();
    }
   calculate_average_2500();
   display_summary_2600();

    printf ("\n\n");
    system ("PAUSE");
    return 0;
}

void intialize_2100(void)
{
total_cust = 0;
total_charge = 0;
}

void obtain_input_2200(void)
{
printf("Enter customer number\n");
scanf("%d", &cust_num);

printf("Enter service code \n");
scanf("%c", &serv_code);
printf("Enter hours of use\n");
scanf("%d", &hours);
}

void process_customer_2300(void)
{
calc_monthly_charge_3310();
update_accum_count_3320();
}

void display_details_2400(void)
{
printf ("Results for customer number %d : \n", cust_num);
printf ("Service Code: %c \n ",  serv_code);
printf ("Charge for one month %f : ", month_charge);

}

void calc_average_2500(void)

 

Yes! Func Calls : 3220 and 4220 keep returning errors of conflicting types and declaration errors!

I reposted the code as I noticed it was incomplete.

Code:

/*
  Program Internet Service.
  
  Add your own documentation.

*/

#include <stdio.h>
#include <stdlib.h>



/* Global Variables */
int cust_num, hours, month_charge, total_cust;
char serv_code;
float  average, total_charge;




/* Function Prototypes */
void intialize_2100(void);
void obtain_input_2200(void);
void process_customer_2300(void);
void display_details_2400(void);
void calc_average_2500(void);
void display_summary_2600(void);
void calc_monthly_charge_3310(void);
void update_accum_count_3320(void);
void calc_bus_charge_4110(void);
void calc_econ_charge_4120(void);
void calc_unlim_charge_4130(void);
void update_accum_4210(void);
void update_counter_4220(void);



/* Program Mainline */
int main ()
{
    initialize_2100();
    obtain_input_2200();
    while (cust_num !=  999)
   {
        process_customer_2300();
        display_details_2400();
        obtain_input_2200();
    }
   calculate_average_2500();
   display_summary_2600();

    printf ("\n\n");
    system ("PAUSE");
    return 0;
}

void intialize_2100(void)
{
total_cust = 0;
total_charge = 0;
}

void obtain_input_2200(void)
{
printf("Enter customer number\n");
scanf("%d", &cust_num);

printf("Enter service code \n");
scanf("%c", &serv_code);
printf("Enter hours of use\n");
scanf("%d", &hours);
}

void process_customer_2300(void)
{
calc_monthly_charge_3310();
update_accum_count_3320();
}

void display_details_2400(void)
{
printf ("Results for customer number %d : \n", cust_num);
printf ("Service Code: %c \n ",  serv_code);
printf ("Charge for one month %f : ", month_charge);

}

void calc_average_2500(void)
{
average = total_charge / total_cust;
}

void display_summary_2600(void)
{
printf("For %d customers, the average is %f:\n", total_cust, average);

}

void calc_monthly_charge_3310(void)
{
 switch(serv_code)
 {
 case 'B':
      calc_bus_charge_4110();
 break;

 case 'E':
      calc_econ_charge_4120();
 break;

 case 'U':
      calc_unlim_charge_4130();
 break;
 }
 }
void update_accum_count_3320(void)
 (
  update_accum_4210();
  update_counter_4220();
  }

void update_accum_4210(void)
  {
  total_charge = total_charge + month_charge;
  }

void update_counter_4220(void)
  {
  total_cust = total_cust + 1;
  }

void calc_bus_charge_4110(void)
   {
    month_charge = 40 + (hours * 0.20);
    }

void calc_econ_charge_4120(void)
   {
   month_charge = 20 + (hours * 0.10);
   }
void calc_unlim_charge_4130(void)
   {
   month_charge = 30;
   }

/* Code/Define all prototyped modules */




Yes! 3220 and 4220 keep returning errors of conflicting ttpes and declaration errors!

I reposted the code as I noticed it was incomplete.