Vehicle in two weeks guarantee repair no result

i took my H1 in two weeks ago for a fault where the battery drains during the night there latest reply is that they do not have spares and it is on backorder. There is also no opportunity for a courtesy vehicle. I called their national call center no reply yet, also their workshop manager promised he will put my vehicle back together and return it and no reply since Wednesday, this after I informed them that my bussiness is reliant on my vehicle. Poor service