Well AFAIK they can't do this, as each account has it's own separate T&C's with different interest rates and penalty clauses etc etc etc.
So they're on to a loser straight away.
have they indicated a reference number at all regarding the new agreement (consolidated figure)?
Don't touch them owe me £500 since January 2019 make excuse after excuse. Seem they always have software problems sending money out. Keep saying they will call back or email nothing been chasing it now for 6 mths the phone staff always have the same banter we will chase it up and get back to you then nothing!