^Now it seems that you've to RENEW/RECHARGE your account for connection to the net again.Though Hardware issues if present has to be sorted out;and according to your info the D-Link DIR-615 is quite O.K.
You have to look out for yourself,whether the BroadBand net connection has resumed to it normal position once again or not after RENEWAL/RECHARGE of your account with You Broadband.
But I have been facing this issue from 5 days before the expiry date...
Sometimes it happens with any ISP(particularly the private ones) who disrupt services to remind the customer,that his/her recharging of account is nearly at its end and the time of recharging/renewing is drawing near(PRE-PAID cases).In case if you had any POST-PAID account,such problems do rarely occur except for any Technical Glitch or Technical/Administration/Political issues from the ISP itself.