Contactless bank cards

A warning to others!
I had my contactless bank card compromised last week while it was in my possession. I only knew when the fraud squad phoned and luckily they were on the ball. My card had been used numerous times that day for on line purchases I had nt done, and they were trying to get withdrawals of £3k.
Seemingly there is a machine you can buy which reads contactless cards by standing next to someone!
I beg of you to buy these wee envelopes you can buy cheaply, eg from Amazon , which does not allow this. I've got mine now. Take care!