Pre-authorization hold from Uber Eats

I have had a horrible experience with Uber Eats and being charged for unrecognized charges. In a space of 3 Weeks I have been charged 6 "Pre-authorization hold" amounts which amount to R492.90 which after reporting to Uber Eats, they referred me to my bank. My bank was able to prove that indeed the various amounts have been debited from my account and that the service provider behind the transactions is Uber Eats. I informed Uber Eats in an email and they told me that the charges to which I am referring "do not exist" on my account. Therefore if these transactions do not exist,where is my money disappearing to under the Uber reference? According to Uber Eats, pre-authorization holds are voided and never processed,but my bank statement which was sent as evidence to them was able to prove that they processed the payments and took money for services I ddi not even receive from their side. This is ***** in it's highest degree and I urge all to be careful when working with Uber Eats as they have proven to be *************.