Bought a ThinkPad in December and in February I discovered that when my routers are set to just 802.11ac ,the laptop won't connect. I sent my ThinkPad to the Lenovo repair center since it is still under warranty. That was mid March. It is May now. I have been checking on the status of the repairs and they have been repairing then holding for customer info then waiting for parts then repairing, then waiting for customer info again about 5 times. I called them today and they told me that they are waiting for a new motherboard. What is a reasonable time to wait for repairs under warranty, and when am I legally in my right to ask for a refund?