Deducting more that what the order is

this is now the 2nd time i order a small meal from the ubereats app and its the second time in a row you deduct more than what the meal is?? what is going on? i ordered for R75 and you deducted R150 from my account. last time i ordered R140 and you deducted R150. the ordered was cancelled and you didn't refund me. can i please get a answer as too what is going on or must i rather not use you anymore?