BAD ,BAD SERVICE AND TRYING TO RIP US OFF FOR THE SECOND TIME.

I visited a doctor at Netcare Pholoso centre with complications with my stomach , i use medical aid that I am a dependent on my husband's medical aid,however a blood test was orderd by my doctor but now i have received a bill from lancet saying i owe them R1500 ,why didn't they use the code prescribed by the medical aid and it is not the first time I had to pay for such ,are you guys trying to rip us off?