Problem with dimmable LED R7s lamp, 8 Watt, 118mm in floor uplighter stroboscope

This floor uplighter is approx. 6 months old. I've changed the R7s halogen bulb against an dimmable R7s LED lamb. First thing: it seems not to be dimmable and the biggest problem: if I turn the uplighter off, the lamb beginns flashing like a stroboscope.

Any ideas? I am not an electrician, so please do not post to technical hints! ;-) Thanks!

• #science_technology
• #led
• #watt_unit_of_power
• #problem_quotation_subject