Repairs take longer than said

I took my phone in on Monday 11/05/2015 for a screen repair. They said it would take 3-5 working days. On Sunday I phoned to ask how long before I can collect my phone. They said it would be within this week. On Tuesday I phoned again and they said they are waiting for parts from the supplier. The supplier was out of stock and had to order. So they only received one part. Now it can take up to 14 days. I understand the fact that the supplier was out of stock, but Vodacom said 3-5 days. And I just feel that if it is going to take longer they need to let the customer know. Don't tell me 3-5 days and then I have to wait 2 weeks.