Citation Pilot reported a GPS signal jam and deviation from course and altitude restrictions while attempting to disconnect the auto pilot.

Narrative

After taking off from MYF; Tower delayed my hand off. When I changed to Departure; the Controller told me I was late reporting. Just prior to that exchange; I had what seemed like a GPS signal jam in that my GPS failed and my ALT did not hold at 3;000 ft.; my clearance altitude. I busted the altitude by about 1;000 ft. while wrestling to disengage the auto pilot. While descending back down to 3;000 ft. the Controller began assigning me fly headings and climb instructions. I reported instrument failures and delayed responding. The Autopilot would not disconnect without pulling the fuse and resetting everything. Meanwhile the Departure Controller began scolding me for having problems while not communicating with him. He said I failed to promptly respond and continued with different fly headings and altitude assignments. He became angry and began lecturing me on how communication should be part of my recovery checklist. The urgency in the cockpit became unnecessarily escalated. While he may have had cause to chew me out; it didn't help the urgency of the situation. A seasoned Controller could have averted some of my miscues.