Lock and Tech USA

I have recently moved from San Francisco. My mailbox lock had to be changed. I called these guys and got connected to Megan, who I think is the receptionist. I sometimes have difficulty understanding when people speak with bullet speeds on the phone. I am not an American and hence sometimes have problems understanding speaking styles.
She was alright when spoken to but when I asked her if she could give some discount, I think at that moment she lost all her sweet demeanor and instantly became rude and lost all her courtesy. Even to an extent that she banged down the phone to my face and my thank you went to a dial tone!!!
Even in-​spite of the rudeness, I decided to go with her as getting my work done was important to me. Next day when I called up again to check on the status of the appointment and mentioned about the discount, she started screaming and banged the phone down on my face again!!!
This is the worst customer service ever where the receptionist is either out of her mind or maybe a really frustrated woman in life… no wonder why these guys are not recommended by anyone and how Al Rovins is, by many commercial buildings.