Pathetic customer service Foschini Stanger

I bought a cellphone at the Foschini store on the 10th of October 2020,the store manager helped me out with completing the sale but failed to disclose that 16th was the last day that i could return the phone should there be a technical issue with the device, i used the phone until the battery died, the phone was very very slow, i charged it on the 12th and it lasted like 2 hours and just went dead, unfortunately i couldn't take it back to the store on the same day as i couldn't get leave from work, i got someone to take it to the store on Saturday the 17th assuming that this was the 7th day only to find out that it was the 8th day and according to the return policy the device cannot be returned but only sent for repairs. I fail to understand how a store manager fails to disclose such important information to a customer knowing that cellphones always have issues, especially the brand that i purchased which was Mobicel.The assistant manager wrote the return details on the receipt on the day that the phone was taken there to be returned, i refuse to accept a phone that worked for 3 days and never came on again. Please resolve this issue ASAP