Displaying model relationship in blade not working

Hello, I have 3 tables, one of invoices one with coletes and one with incasaris.

I have the following code:

    <?php

    namespace App\Models;

    use Illuminate\Database\Eloquent\Factories\HasFactory;
    use Illuminate\Database\Eloquent\Model;
    use Mail;
    Use Illuminate\Support\Facades\Storage;
    Use App\Models\Incasari;
    Use App\Models\colete;


    class Invoice extends Model
    {
    use HasFactory;

    public function incasari(){
    return $this->hasMany(Incasari::class,'i_plati_id','id') 
     ->selectRaw('incasaris.i_plati_id,SUM(incasaris.i_totaleuro) as totalincasat') 
     ->groupBy('i_plati_id');
    }



    public function colete(){
    return $this->hasMany(colete::class,'invoice_id','id') 
    ->selectRaw('coletes.invoice_id,SUM(coletes.totaleuro) as totaleuro') 
    ->groupBy('invoice_id');
    }


     }

In my controller the following function:

    $invoices = Invoice::with(['colete','incasari'])->get();

returns me the data I want when I use DB($invoices)

However, when I want to access the relation in my blade view as:

    @foreach ($invoices as $invoice )
                                                 
                                                                                             
    <tr>
    <td> {{$invoice->id}} </td>
    <td> {{$invoice->serieId}} </td>
    <td> {{$invoice->colete->invoice_id}}  </td>
    </tr>
    @endforeach

It returns: Property [invoice_id] does not exist on this collection instance.

But, If I use :

    @foreach ($invoices as $invoice )
                                                 
                                                                                             
                      <tr>
                         <td> {{$invoice->id}} </td>
                         <td> {{$invoice->serieId}} </td>
                         <td> {{$invoice->colete}}  </td>
                            </tr>
                            @endforeach

It returns me the data as:

    [{"invoice_id":2008,"totaleuro":"3000.00"}]

I am pretty sure this is a syntax error but because I am new to Eloquent I can't really figure it out where