Exchange

i bought a pair of shoes early in the month ,when i want to do an exchange they don't want to assist as iv lost the slip and the teller did not take my number so that i can get an sms invoice she says the system was offline , only when im wanting to do an exchange she tell me the system was offline for smsing. 0% on willing to help even if they see its there product and they remember me from the day of the purchase