Material-friendly fastening for a jersey

Our customer wanted a material-friendly way to attach his jersey.

Material-friendly fastening for a jersey

Hello Magnet Shop Team,
I bought this jersey frame: the jersey is supposed to be fixed to a foam board with pins.
However, the pins don't hold.
For this reason, I bought magnets from you disc magnet Ø 20.0 x 7.0 mm N40 nickel - holds 8.5 kg, which now hold the jersey with metal disc Ø 20 mm with hole and countersink nickel on the other side of the non-magnetic foam board. Now I need to monitor the connection over time to see if it's strong enough and if the jersey slowly slips down due to gravity. With a holding force of 8.5 kg, I thought I had chosen sufficiently strong magnets, but they aren't holding incredibly securely. If the jersey does shift, I'll have to replace the foam board with a painted steel sheet to achieve a stronger magnetic connection. I hope you find my application interesting and innovative. ;-)