Not given enough - missing antibiotics

[Rflowerco]

Hi all
Just popped into a pharmacy because we were due 105 (only given an 100ml bottle).
Explained we were missing 5ml, and the workers at the pharmacy told me that the pharmacist that drew up the amount wouldn’t of felt the need to give the extra 5ml as it would of meant opening another bottle?
Surely this cannot be right?
I’ve just rechecked the bottle at home, and there’s no way I can even get another 3 more doses out, so I reckon we are missing at least 30ml, which is a days worth of antibiotics for our child.
They tried to convince me to go back to the doctor, or to a walk in, and start another course - if I feel that there is still a bit of infection.
Also stating that 5ml isn’t that much anyway and wouldn’t do much for her.

Not sure how to get the extra bit of dosage that we are missing without them getting defensive, or feeling like it is necessary to hand over? Especially if it looks like it hasn’t been drawn up accurately, regardless of the amount they ‘owe’. My mums a nurse and said it’s not their job to hold back any ml’s, and that no matter how small because you can always get leakage when drawing up doses too.
Any advice please would be much appreciated. With thanks

What dosage have you been ask to give 30ml a day seems high

Also it would potentially need to be another bottle as the pharmacist just adds water to it (I have done it before) so would mean opening another one which makes 105 ml and odd choice by the doctor

bottles usually hold more so the pharmacist could have popped in the additional 5 mls. i'd speak the the pharmacist who filled the prescription and not bother with the clerk. you might just have your full 105 in the bottle.