********** use of my old closed account

I'm one old customer from Jet I had an account with them since 1996 while they were stil called Sales House. In 2017 I paid up and closed this account with this retail store and to my surprise in September while my number was *******ly ported a purchase of Airtime was made through this account and yet again in October. Something is very fishy to me about these purchases taking place while my number was locked under ********** port. Kindly investigate thses purchase s. What's worse is this airtime vouchers are purchased in a large amounts.... Isn't that strange Jet? I smell a dead rat