Discovery Health (non)service

Discovery health deducted payment for my oncology treatment from my Savings account. (I have full oncology benefit which Discovery approved). Despite phoning Discovery and reporting their error they have still not corrected it. I had to go for 2 dental procedures with Dr L Riddle (dentist) and I had to pay cash as Discovery reported that I had no Savings left. I believe Discovery's customer service leave much to be desired. I am sick and tired of the embarrassment they are causing me!!!