Just respond saying, please note my correct residential address for all future communications. Also that Lowells will need to contact 02 about the account, as there has been a recent change, which will need to be taken into account. That a formal complaint has been registered with 02.
Suggest that you contact 02 in writing to register a formal complaint about their handling of the account and the unauthorised debit to your Bank account, which your Bank have recently reversed.
I expect that someone with specialist knowledge will arrive to give you some good advice soonish. In the meantime, do you realise that after two years employment you then have a certain security. You say that you have been working for over a year. This means that if you rock the boat too much you could be vulnerable to some kind of retaliation.
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!