Tax Invoice

I booked my car for service and i was helped by Zelda.<br> <br> when i went to pick up my car she told me the internet was down she will write a receipt for me and will email me the tax invoice to show what job was done on my car, in the morning of the 04/11/15 i waited for my invoice as promised but didn't get it i called 4 times requesting the same thing still haven't received it. the last call i was put on hold for a good 5 min when the person on the other hand picked up she said hello once and put the phone down. I'm asking myself why is it so hard to send me an invoice? what should i do to get my invoice? my understanding was when collecting your car after it has been serviced you are been told what job was performed but in my case i did. Please help me with my invoice i need it.