How to recover messages on phone with old number?

I recently traveled to a foreign country and because my phone didn't work, I had to purchase a new phone and a new temporary phone number. I activated the new number on the phone, then enabled what's App on it. Everything worked great. I used it during my stay in this foreign country. I backed up all my What's app messages.
A few months later, my phone number was reallocated to someone else and my what's app connection on that device was lost. I still have the backed up messages ... but can't seem to figure out how to pick them up. The messages are encrypted and whenever I tried to retrieve them, it ask me to connect to the old number, which I don't own anymore.
Any chance I can recover the backed up messages?