Delete data in chained dynamic list using C language

Question

Good afternoon. I’m doing a project for the college where the teacher asked to create an algorithm with dynamic lists, where one list should contain customers and another, products. The goal of the project is to make the CRUD of both lists, on the condition that the customer cannot be excluded if he has any product attached to it. The rest of the algorithm I managed to do, but I stopped at deletion. Could you help me? Since the code is kind of big (about 600 lines), I put it in Git instead of posting it in text here.

https://github.com/GabrielManiza/structured

I really appreciate the patience and all the help you can give me!

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EDITION: The part that is giving me problems is how to check if the customer has products. I need to delete it if you don’t have it and keep it (showing an error message) if there are related products. In my code, the function that is responsible for this (and not working) is:

struct listacliente* remove_ordenado(struct listacliente *inicio, int x)
{
    struct listacliente *p,*q;
    p = inicio;
    q = inicio;

    while(p != NULL)
    {
        if (p->info.codigo != x)
            p = p->proximo;

        else if(p->prod != NULL)
                {
                    printf("O cliente tem produtos cadastrados e não pode ser removido.\nPor favor, remova todos os produtos e então tente novamente.");
                    break;
                }
            else
            {
                inicio = removeInicio(inicio);
                return inicio; 
            }
    }

    if (p == NULL)
        printf("\nCliente não encontrado!");