It sounds like there was some sort of payment irregularity, and you’ll need to talk to BA directly. Though if you had a 125 prefixed ticket number it’s surprising it was suspended, in my experience if there’s a payment shortfall you don’t get ticketed at all or they call you.

Something doesn’t add up here. Was the booking made on your own BA account? Do you fly regularly with BA? Was it a cash or avios booking?

Actions from here: decide if you want to travel now and look at options. Call BA to get a detailed explanation. Put in an EC261 claim for involuntary denied boarding which should at least flush out the reasons for the ticket problem eventually.