Help!!!

I seriously need some help. Dell have had my laptop now for two weeks, to fix a fault they caused on a previous repair (should have been a straightforward motherboard swap). However they have had the laptop for ages and claim there are other problems with it that didn’t exist when it was sent (resulting in them fitting 2 New battery’s (as one was fault which took them 3 days to realise), LCD screen replacement and a new heat shield along with the new motherboard. I keep being given different version of events and different dates I would receive the laptop and have been told of they can’t fix it within 10 working days they would issue a replacement. However there 10 working days are up and they say the repair is still on hold due to waiting for parts (although they refuse to say which parts) and now don’t have the ability to issue a replacement (despite being told they could only recommend such action after 10 working days). Is there anything I can do as I desperately need a laptop to apply for apprenticeships? They refuse to offer a  loan or replacement laptop and suggest I wait for their service. Is this really my only option?