Harley Benton TUBE15 Celestion

A perfect combo - in the beginning that was what I thought. It really was, amazing sound for such a price. However after some months the problems have started. First problem I had was when I attached my guitar pedals from Send/return channels. After using it that way, if I plugged off the pedals from send/return channel there was no sound. I had to use the amp by attaching a short jack-jack cable to the send/return ports, only this way sound would come. I reported this issue to thomann, they issued a return. All good till here. But when I received my amp back, I noticed a new problem... When I was playing my amp would sometimes go mute after some crackling noises. It was very frustrating to play this way, especially when you record. I opened another ticket and another return invoice came... Again some weeks without amp and here it comes. The "repaired" amp... Again I have the same problem in the end, I don't know what was repaired, but surely not the problem I've mentioned. Very frustrated with this product