You must have been using a flimsy chain, I would only use a chain that's 12mm-14mm. If you can't afford a good thick chain and a good padlock. Then just go with a Onguard/Abus/High Level Kryptonite U lock. Then use a cable for the front wheel and frame/Armored cable if you wanna be really secure. Abus makes a braided cable that's wrapped in 5mm steel plates. I have 3 different sized U-Locks and 2 different cable locks depending on where i'm heading to decides what locks I bring with me.