App not helpfull

I tried to make a call 2 days in a row where I was on hold for 30 to 40. Eventually I was assisted and the lady explained that they were very busy. I was fine with that. I called to block a lost sim and cellphone. (second device) I only managed to block the sim card since I didn't have the imei number at hand. After the call I checked my app since this second device is on my contract and the imei should appear on their. Unfortunately I don't have the box or papers for this device since I recently made a temporary move. This device did not appear any ware on my app?? No info whatso ever. The lady I spoke to earlier around 14h00 told me I could fone back after 17h00 when I get home to report with the imei number. But call center is closed?? (135) How must I do my claim if their is no assistance after 17h00. As this might be my only after hour time to do this. A few month ago I had to same issue. I have been a customer with you for more then 5 years. And I must say the follow up and insurance is not too good.