Discount Tire Centers Stripped Threads on My Oil Pan and installed a new Plug Crooked so It Leaks Oil in North Hollywood, California

On 1-22-13 I entered Discount Tire Centers of North Hollywood, CA to get my oil changed.  They informed me that (they) stripped my oil pan threads and tapped in a new drain plug.  Upon getting home I noticed an oil leak.  Took the car to my mechanic, they told me the plug was put in askew and would leak oil from now on, the only fix was to replace the oil pan.  I contacted the owner and got no repsonse. Contacted the regional manager and Mr. Mike Nelson forwarded my info to Akop Semerdjian the owner - who then communicated to me through Mr. Nelson that he was not responsible.  I then paid the $300 out of my own pocket to fix the damage they caused.  I have continued to contact Discount Tire Centers for my $300 and they are now ignoring me.