It sounds like the charges you mentioned for discounts on medicine purchases represent additional fees rather than straightforward discounts, and not providing a receipt or acknowledgement is concerning.

⚠️ Possible Reasons for Charges and Missing Receipt

• Some shops may levy a handling or service fee when applying discounts, but this should be clearly communicated upfront.
• A charge for a higher discount (like Rs 150 for 20%) could be a fee for using a special offer or a particular payment method.
• Not providing a receipt or any form of acknowledgement is against standard business and legal practices, as customers have the right to proof of purchase.

🩺 What You Should Do Next

• Request a detailed explanation and an official receipt from the medical shop management.
• If they fail to provide a valid receipt or proper clarification, consider reporting the issue to consumer protection authorities.
• For future medicine purchases, always insist on a receipt for your records and to ensure transparency in charges.

I recommend consulting directly with the pharmacy manager or, if unresolved, a consumer rights advisor for further help.