Insulted for missed payment

<br> <br> I took a Samsung phone from Westgate mall last year November or December with a knowledge of that my first installment will be end of February of which i may have been mistaken and i was called about it and i informed them that i thought it was end of February but did make arrangements that i will pay double because i missed my installment,which i understand and i accept.<br> <br> Now on the 22/2/16 i don`t understand why should i be threatened with sms ` s and when i call about the sms i was blatantly insulted by a lady by the name Natasha she was so rude that i will never ever buy anything from house and home