Billing on previous number

Please kindly contact me as I require help and have contacted customer services on numerous occasions for help with my previous number (virgin mobile) which was changed without my knowledge and I never had to pay any bills before as they were always taken automatically so I was never aware of any final bill and the whole time all I’ve wanted is to recover my own (“old” original Virgin Mobile number). I’ve been told it’s gone to recovery etc. all this is quite shocking to me never ever expected such to happen as was a Virgin customer for several years always paid by direct debit. Please help.