Farzana Patel visited the centre:mk and Midsummer Place on Tuesday December 28 and was horrified when she realised she had lost her phone, bank card and money.
She had left them on a seating area outside Hobbs store when she took a break from shopping.
The bank card was tucked into the phone case, along with cash and gift vouchers she'd plan to spend.
"I only realised about 15 minutes after I left the centre. My friend called my phone, and one very, very decent, kind and genuine man answered and said he found it and was keeping it safe for me," said Farzana.
"He patiently waited for me outside the Primark dressing rooms. I was so grateful and all he asked for was a handshake, bless him.
"I didn't ask his name or say much as i wasn't thinking straight. Afterwards, I really wish I had asked his name and done more to thank him.
"He was a tall white British man with glasses. If anyone knows who he is, I'd really love to know."
Farzana concluded: "In the meantime, i make a heartfelt prayer to God to bless him and his family with peace and prosperity and to keep them happy always. It's the least I can do."