received 200 Points instead of normal 10 E credit when buying simcard

!Hi, I bought an o2 simcard for 20 euro and asked to have 10 euro credit and not the 200 point package (because i sometimes use it internationally). Now i wrote a message to a mexican phone nr and I ran out of credit right away. I asked the store where I bought for help and they explained that they booked me the 200 points instead and that they cant do anything. Please help, how can I get my credit back? Thank you (In case you need, year of birth 1987) You can check my call history there. Thanks! !